BW35 strip and rebuild in pictures

[eightofthem (Andy)]

Time to reassemble the rear hub now.
If the bearing is worn you need to change it before reassembly of the hub. Then give everything a good clean.



New bearing ready to go in



And fitted ( Be sure to fit it below the chamfer, or the shaft will foul the bearing. See top picture it shows the position clearly )




The first parts to go in are the piston seals here.




And here.



Dont forget to check the valve is free, give it a rattle, it should close with light finger pressure.


The piston then needs to be installed in to the hub using the correct tool.


when this returns you need to set up the hub on your compression tool, and refit the spring first.



Followed by the collar.


Then the circlip ( this needs to go over the threaded bar first unless you are using M8 or M10 studding then the gap may be big enough to slip through )





Then place the tool over the rod and compress the spring, and refit the circlip. It is a bit fiddly but use the chamfer on the hub where the steel thrust washer sits to help start it off.


Remove the tool, and get ready to refit the steels and frictions.


Remember these are dished and as pointed out earlier, these need to be refitted with dish side of the steels all facing the same way.
ie all facing up / or all facing down. Check each one in turn with a straight edge.


I am using new steels, and new frictions. If the steels are new they will have a protective film on them. This needs to be cleaned off before fitting them.
And the frictions will need to be soaked in new trasmission fluid.
There is also something amiss with this next picture. Can anyone see what it is?


Then is a case of fitting them. Steel first ( dont forget the dish)


Then a friction.


Until you reach the last steel. ( this is thicker than the rest and flat on one side, flat side to frictions )


Then refit the snap ring.



Next turn the hub over to refit the three sealing rings.


Go on give them a bit of vasaline.
Slip them over and join them together, they have half lap joints on them.


Turn the hub back over, and refit the steel thrust washer first, in its location.




Then refit the bronze thrust washer on top.



Then re unite the hub with its sun gear shaft.


And refit the shaft into position making sure the needle bearing has not fallen off the shaft.
Put it all into a clean bag for now, its done with.



Next in the firing line is the planet set, and rear brake band.


We will start here next time.

[harvey]

Mar 5, 2013 20:03:48 GMT eightofthem (Andy) said:

There is also something amiss with this next picture. Can anyone see what it is?

Yes, but I'll give everyone else a chance.

[eightofthem (Andy)]

I knew you would spot it.
O Master.

[eightofthem (Andy)]

Right we are off again, had more shed time and cups of tea with camera in tow.
So we left off here last time, with the planet set and rear brake band.



First to come off is the center support, it fits snugly in the hub, just lift it out.






If you have not already taken the brake band off to look at it, now is the time to do it.
As you can see the brake band has been run down to excess.




It is supposed to look like this.


So because the friction material has worn away to the metal, this has now ruined the planet set where it runs.
Nothing else for it but to replace it. Now i have read that thicker friction brake bands are available, which makes me think that the planet set could be machined
back smooth as long as the wear is not to excessive, or prehaps a sleeve could be made to fit over the set. This is beyond my capabillities, and would need the services of a good machine shop, so depending on where in the world you are this might be an option to look at if a replacement set is not available.



So i will press on with looking at this one, just to point out other faults to look for
Next remove the needle bearing located at the back of the planet set.
It has its own thrust washer attatched to it.




Turn the set over and remove the one way clutch.



Next there will either be a snap ring or a wire retaining the outer race for the one way clutch.
The wire will be hard to spot if the hub is mucky.


Either way remove it.



Then the outer race can be removed.
There are three reccesses that you can use to lever the race out. Be careful not to damage the outer edge of the planet set ( use packing )


Lever each segment out equally a bit at a time.


Until you pop it put.


You now have a good view of the internals.


So there is the planet set laid bare. Lets look at it for wear.


So we know that this one is stuffed because of the brake band wear.



Check the bearing in the planet set for wear and replace it if its worn or damaged.


Use the tool made earlier, and some tube, or sockets to remove it.




Check all the gear retaining pins are secure.


Lots of bits tend to end up lodged inside here, and do lots of damage.


You can see that debris has been lodged in the bearing surface for the one way clutch, and killed it.


Also the one way clutch is showing signs of wear, and has a lot of sharp edges because of it.


Looking inside the front of the set look for wear at the gear ends. These are packed out with washers and they tend to wear away causing excessive movement in the gear.


This can be seen here, the washer is no longer there. and the gear is now running on the wall of the planet hub, and eating it away.


Causing excessive free play.


Just another view of the same gear from the outside.


Check out the center support for wear along the contact points.


Also when you are cleaning it all, blow these holes out with your airline.


I found these chunks living inside the planet set.
They caused havoc with all they contacted.
I could not find where they came from, my only conclusion is they are from the casting process of the main case, and broke free ending up here.




Once you have checked all the components for wear, it needs to go back together.
Starting with the outer race for the one way clutch.


Locate it in the slots, and tap it home with a soft copper hammer or the likes of.


Then refit the retaing snap ring or wire. The replacement has a wire.


If you have the wire type locate it in its groove, and avoid placing the join in the slot areas.


Make sure it is fully home.


Then refit the one way clutch.


It is a bit fiddly, you have to squeeze the bearings and retainers in together.


There you go.
Once in place you know you want to, go on cover it in Vasaline, or coat it in new A.T.F.



Refit the center support.
Once in position the operation of the one way clutch can be checked.


Once in position the operation of the one way clutch can checked.
The clue is in the name, it should only rotate one way, clockwise. Hold the planet set with one hand, and turn the center support clockwise with the other hand.
It should turn freely, Try to turn it back anti-clockwise, and it should lock and not turn at all. Then try clockwise and turn it and try anti-clockwise again and check it locks.


Then turn it over and refit the needle bearing ( thrust side against planet set ). Smear some Vas on each side to retain it in place.





Place your new brake band with it, and put it away for now in a clean plastic bag.
you are done with it for now.






Next time the output shaft and ring gear are in for it.
We will start here.

[eightofthem (Andy)]

And we are off again.
The output shaft is next.



Firstly, remove the thrust washer, and check it over for wear.





Then remove the three sealing rings from the shaft.


New ones come with the rebuild kit.


Then remove the snap ring that holds the ring gear to the output shaft.


And remove it



Then lift the output shaft off the ring gear


So there is the components of the output shaft laid bare.


Dont be tempted not to split the ring gear off the shaft.
Lots of nasties tend to take cover there.


Clean all the parts down, and check the shaft for wear or scoring where it runs on the rear case bearing. Blow the holes out with your airline
Then refit the three new sealing rings to the shaft.

.
Stager the joints



Refit the ring gear to the shaft
And refit the snap ring


Give the base a smear of vas to hold the thrust washer in place.


And refit it (tabs up )


Thats it. Nearly ready to start refitting some items to the case, just a few more bits to look at, mainly the two servos, and the governor which is next up.



So we start here next time, with the governor.

[eightofthem (Andy)]

Off we go again then.
We left it here last time, with the governor waiting.


There are a few variants of the governor, i can only show you what i have fitted to mine.
So firstly, remove the retaining nut and washer.



Then you need to pinch the bob weight with your fingers like so.



To expose the small circlip, or "E" clip that retains it.


Remove it.


Then slip the bob weight off the valve stem.


Then remove the valve stem, and spring from the center of the governor, ( the only way it will come out )


Then the small piston, or valve


There is the governor, and all the bits.
Clean it all down, and inspect it very carefully for wear to the bore and any damage.
If in doubt replace the whole unit ( dont skimp on it )


Then reassemble the lot in reverse order, and check the movement of the valve spring by pinching it in and out.


Next is the rear back plate.
Clean this down and blow the holes out with your air line.


Look for any wear or scoring on the face side, and check the inside of the cylinder for wear or score marks.



Servos next.

[harvey]

That's the late type governor. One thing to note when refitting it is that the spring washer that goes under the big nut doesn't get fully compressed.Once it's on it can be air tested.

[eightofthem (Andy)]

Thanks Harvey.
The earlier type of governor looks a bit fiddly, this one seems simple to look at and strip.
I did notice the spring when I took it off the shaft, but I guess when the location pin on the nut is fully home that's the lot.

[David]

I am so impressed by this step by step guide Andy and the clear photos.
Can you put something together from the content on this forum, for Take Five?

[eightofthem (Andy)]

Yes David no problems.
Only trouble is it would run over the next thousand issues
As I said at the start of this thread I am no expert on these, Harvey is the man.
It will depend on how much you would like to have in the mag, if you would like it as is and spread it over lots of issues that would be fine by me.
This is not the type of repair many owners will take on themselves, but it is very interesting to see how everything works in relation to each other, and It does give a good insight into what goes wrong any why, and what needs to be done to avoid it going wrong, this was my intention from the start, and with others passing comment on there own experiences and tips, a good reference page could be established for people to turn to when the need arrises
I bet there is a good many things I have missed doing this, but it is just a guide and not gospel.
Send me a PM on what you would like.
Andy.

[johnwp5bcoupe]

Mar 21, 2013 15:07:23 GMT eightofthem (Andy) said:

Yes David no problems.
Only trouble is it would run over the next thousand issues
As I said at the start of this thread I am no expert on these, Harvey is the man.
It will depend on how much you would like to have in the mag, if you would like it as is and spread it over lots of issues that would be fine by me.
This is not the type of repair many owners will take on themselves, but it is very interesting to see how everything works in relation to each other, and It does give a good insight into what goes wrong any why, and what needs to be done to avoid it going wrong, this was my intention from the start, and with others passing comment on there own experiences and tips, a good reference page could be established for people to turn to when the need arrises
I bet there is a good many things I have missed doing this, but it is just a guide and not gospel.
Send me a PM on what you would like.
Andy.

Keep up the good work Andy

[eightofthem (Andy)]

Thanks for your support chaps.

We are on a roll now,and heading towards replacing it all in the case.
Servos are next on the agenda.


Starting with the rear servo first.


First to be removed is the spring.
This is quite a meaty one, and it dont half hurt if you you dont prepare yourself for it when you flip it out of the retaining tab.



Anyway take care when you release it.
When the tension is off it, just slide it off the steel peg.



Then you have to drift out the steel peg from the case, it also retains the lever arm.
It is not that tight.


Just make sure you tap it out the obvious way ( The peg has a chamfered end, which is flush to the case. )


Once the peg is out, the lever arm is free.
Lift it out.


Then the piston is free to be removed.
Try to pull it out first, if that fails you can use your airline to pop it out.
Go easy though not too much pressure, and apply the air to the hole where the metal feed pipe was fitted here.


/

Then remove the piston from the bore.


As you can see the seal has broken, this may have had an effect on the outcome of the rear brake band wear.


Then you are left with the empty case.


So there is the rear servo laid bare.
And as Harvey pointed out, the link arm that operates the brake band is or should be stamped with 215.


Give all the parts a real good clean.
Check the bore for wear or damage, and give the feed hole a blow out with your airline.
Check the rest of the case for damage and wear.


Fit a new seal to the piston ( these come with the kit )
Use the correct size.


Better than the old one i think.


Give the lot a good coat of vas or new ATF fluid.
And refit the piston back into the servo this way up




There it goes.


Replace the lever arm next.


Then the retaing pin.
If you have the back of the servo towards you fit from the left, chamfer side first.


Line it up with the lever arm, and tap it through just flush or slightly proud, not too much or the spring will not fit on the peg properly.



Then the meaty spring, you can only fit it the right way.


Make sure it is the right position on the peg, after you have relocated it in the retaining tab.



Job done. This can be tested once refitted back on the case.
Put this in a clean bag for now.


Front one next time. ( unlucky for some )

[eightofthem (Andy)]

Front (unlucky for some ) servo
This is the self adjusting type, so it does what is says.
Many are fitted with a manual adjusting one, where the sump has to be removed to adjust it.
The method to overhaul them are the same, just the refitting and adjustment method in the main case differ.



First off remove the adjustment bracket and retaing bolts,if you have them in place.


Then there is a circlip that needs to be removed.
This holds the piston in.



Then the piston can be removed.
you can pull it out, or if it is a bit stiff, use your air line like the rear one,by applying air here.




Then remove the piston spring.



As you can see, this seems to be a place which retains a lot of crud.
Needless to say it needs to be cleaned out.


There are three seals on this piston, and it comes apart to become two items.


Like so.


Strip it down, and clean it all, remove the three seals.
Check it all over for any wear or damage.


Give the house a good clean, and blow out the holes with air.
Check the bore for any wear or damage.


Check the lever / pivot arm for any wear, especially where the link arm sits.
Drift out the retaining pin, as you did with the rear servo, and look it over for wear.


Once satisfied with the condition, fit new seals to the pistons ( these come with the kit )
use the correct sizes, and lubricate the new seals.






Then refit the two halves together. Give the lot some vas.




Check the condition of the spring.
I did see a measurement somewhere that it should be, but i cannot find it now.
If you know give us the answer.


Refit the spring back in the housing.


Then the piston can go back in.
Make sure it goes in square, and give it a good coat of vas or ATF.


Press it fully home, enough so the circlip can be refitted.


And refit the circlip.


Check it is fully home.


There you go.
The steel link for the brake band is also stamped 215, just like the rear one.
This is because there are variations of these for different makes of car.
As this is the self adjusting type, there is a settiing for the adjustment spring which sits on the steel bracket.
I will show you this when we come to refit it back in the main case.


The main case now looms closer to be refitted with all the new bits
oooooooooooo excited.
This needs to be cleaned, and checked over.
We will start here next ooooooooo :Do excited

[johnwp5bcoupe]

Andy a suggestion how about doing a CD/DVD when complete I for one will buy one

[Deleted]

Mar 23, 2013 10:05:09 GMT johnwp5bcoupe said:

Andy a suggestion how about doing a CD/DVD when complete I for one will buy one

Yes, that's a good idea. I would buy one for reference purposes.

Question please!

I noticed recently that the kickdown switch under the throttle pedal was stuck so I freed it up.What purpose does this switch have as my reading of the w/m is that the kickdown facility is controlled by the downshift cable. There doesn't seem to be any electrical or other connection so was its purpose simply to act as a indicator that the driver was about to drop a gear depending on roadspeed? I'd forgotten about the kickdown and until I next use the car, I'm not totally sure if it's working or not.

[eightofthem (Andy)]

I dont know if there is a need for a DVD, as it is all on here.
If you would like one I will burn you one for free, but it would be pictures only for now as I have not made one with the captions as yet.
As for the kickdown mechanism, it does what it says, you press the pedal down hard which instantly selects a lower gear, the actual switch under the pedal is to give the pedal some resistance against accidental kickdown, in other words you have to give some right foot.
The kickdown speeds are limited to prevent the engine going off on one, and you are right it is cable activated by funnily enough the kickdown cable, it just shifts the gear for you instead of using the selector.
I had the wrong kickdown cam fitted on this box i am doing now, well spotted by Harvey, so i will go into this a bit when it comes to looking at the valve block.

[eightofthem (Andy)]

Right I have had my cuppa so I am ready to post some more pics.
It is time to start looking at the main case in preparation for refiting the internals.
We left off here last time.


For starters if your case looks like mine did when i started, and you intend to keep it looking rustic
then thats fine, but you will end up inviting some of this stuff inside for lunch on your shiny stuff.


It does need to be clean, not just for cosmetics.( maybe not to this extent i am just sad and have two girls to escape from )


At the back of the case you will find a bearing which the output shaft runs on.
Replace it if damaged or worn. They are available.


Turn the case on its side and check over the selector mechanism.


I removed mine, just because I am a keen to see how it works. You dont have to, unless it has lots of free play.


While it is out I could check the condition of the pegs that the linkage moves on for wear.
Also a good time to check the condition of the park pawl arm and linkage.


If you do decide to take out the mechanism, dont loose the spring and ball located under the selector arm.


Replace it all and check the operation of it.
Also a good time to replace the seal on the outside of the box on the selector arm.


You need to recover the back plate out of storage



And the output shaft.


Before you start refitting you need to remove the three special bolts that retain the center support.


Two located here.


And the long one here.



Once they are out remove the bronze thrust washer from the output shaft.


Turn the main case so the front ( bellhouse ) is up in the air.
It will help if you have a pair of tressles that you can sit the case on, as the output shaft will need to dangle through the middle.
Place a good smear of vasaline here. Here we go ooooooo excited


And place the thrust washer ( bronze side up tabs down ) in position.
It has three tabs which you need to locate in position where it is recessed like so.


Then the output shaft can be installed.
Plenty of vas on the shaft and around the bearing on the case please.


Feed it fully home, and then make sure that the thrust washer did not move from its spot.
Engage park with the selector, this will help to keep the shaft in place.


Next slide the back plate on over the shaft, take care not to damage the three sealing rings.
It helps if you keep one hand on the output shaft in the case to stop it moving.



Plenty of vas again, and line up the holes here.


Refit the five retaing screws.
And tighten to 4 / 5 lbs ft.


Then the governor can go on.


Remove the retaining nut and washer.


And replace it on the shaft, with this face towards you ( if you have the later type that is )
That square slot needs to be facing the tail end.


Line up the hole on the shaft, and refit the nut and washer. Tighten it up.
As Harvey pointed out earlier, the spring washer will not sit flat, once the locating pin is fully home it can go no more.


You can test the operation of the governor by using compresed air to mimic fliud pressure.
Apply here.


And you should see the bob weight move here. ( also notice i used a cable tie behind the governor to help keep the output shaft in place.)


Next to go in is the rear brake band.


Bit fiddly, and it needs to go in at an angle.


When you have it in position just check that the band adjuster is in the correct position.
It is oval in shape, as you see here the oval is sitting vertical, adjust it so the oval is horizontal to the case, it seems to sit better in the brake band slot.


Then position the band in place.


Now the planet set and center support can go in.


Before it does check that the needle bearing is still in place, and the correct way around.


You need to line up the retaining bolt holes to the ones on the case here.


And here.


Get a grip!.
Go steady it is heavy. Feed it into the case and monouvere it into the output shaft and through the brake band.




Those holes then need to line up, one is for oil feed, the other for the retaining bolt.


Move it around so that the bolts go in easily.
If the bolts are tight, it is not in the right spot.
This long one just finger tight for now, as is holds the servo as well.


Then refit the two 9/16 bolts on the outside of the case.



Torque these two 9/16 up 10 / 13 lbs ft.


Next to go in will be the rear clutch hub and sun gear shaft.
We will pick this up here next time, as i need to have the front and rear clutch pistons installed properly by my hero Harvey. My tea has gone cold now!

[Deleted]

Mar 23, 2013 11:43:29 GMT eightofthem (Andy) said:

I dont know if there is a need for a DVD, as it is all on here.
If you would like one I will burn you one for free, but it would be pictures only for now as I have not made one with the captions as yet.
As for the kickdown mechanism, it does what it says, you press the pedal down hard which instantly selects a lower gear, the actual switch under the pedal is to give the pedal some resistance against accidental kickdown, in other words you have to give some right foot.
The kickdown speeds are limited to prevent the engine going off on one, and you are right it is cable activated, it just shifts the gear for you instead of using the selector.

It was the term switch that confused me, so it's just a warning "click mechanism" rather than a functional switch?

[eightofthem (Andy)]

Yes it also pushes the pedal back to normal position, I guess the click is a driver sound aid?.
The pedal must return from the kickdown position, or the poor autobox will not know what is happening to it.

This picture shows the kick down cable where it locates the cam inside the autobox.
The long shaft is the selector shaft, which is moved via the gear selector in the car.
The short one behind it, is operated via the cam, which is rotated by the kickdown cable, which is operated by the drivers right foot.
When this is activated the valve block works its magic, and sends fliud presure to where it is required to select the next lowest gear, then vroooom off you go.
Sorry it is not scientific, but that is how understand it.


So a good point to add here is this.
If the cable is too tight the cam could be be pushing the selector, thus pushing fluid and confusing the shift pattern.
Too slack and the cam will not rotate enough to operate the selector, thus not operating kickdown.
Correct adjustment is vital to good health and operation of the box.

[johnwp5bcoupe]

Mar 23, 2013 11:43:29 GMT eightofthem (Andy) said:

I dont know if there is a need for a DVD, as it is all on here.
If you would like one I will burn you one for free, but it would be pictures only for now as I have not made one with the captions as yet.
As for the kickdown mechanism, it does what it says, you press the pedal down hard which instantly selects a lower gear, the actual switch under the pedal is to give the pedal some resistance against accidental kickdown, in other words you have to give some right foot.
The kickdown speeds are limited to prevent the engine going off on one, and you are right it is cable activated by funnily enough the kickdown cable, it just shifts the gear for you instead of using the selector.
I had the wrong kickdown cam fitted on this box i am doing now, well spotted by Harvey, so i will go into this a bit when it comes to looking at the valve block.

It would be a shame after all your brilliant work to loose it if the hosting went down

[eightofthem (Andy)]

Dont worry, the captions will stay, and the pictures are saved on P.C disk and card.
If the worst does happen, and the pics do go missing I will re-do them.
The disk is a good idea, and when time permits i will do a proper job with one, Harvey can have the first one
as well as you two,I could send the club a copy, and they could rattle a copy off as and when required.

[johnwp5bcoupe]

Mar 23, 2013 13:56:32 GMT eightofthem (Andy) said:

Dont worry, the captions will stay, and the pictures are saved on P.C disk and card.
If the worst does happen, and the pics do go missing I will re-do them.
The disk is a good idea, and when time permits i will do a proper job with one, Harvey can have the first one
as well as you two,I could send the club a copy, and they could rattle a copy off as and when required.

Super Andy

[Deleted]

Mar 23, 2013 13:43:34 GMT eightofthem (Andy) said:

Yes it also pushes the pedal back to normal position, I guess the click is a driver sound aid?.
The pedal must return from the kickdown position, or the poor autobox will not know what is happening to it.

This picture shows the kick down cable where it locates the cam inside the autobox.
The long shaft is the selector shaft, which is moved via the gear selector in the car.
The short one behind it, is operated via the cam, which is rotated by the kickdown cable, which is operated by the drivers right foot.
When this is activated the valve block works its magic, and sends fliud presure to where it is required to select the next lowest gear, then vroooom off you go.
Sorry it is not scientific, but that is how understand it.


So a good point to add here is this.
If the cable is too tight the cam could be be pushing the selector, thus pushing fluid and confusing the shift pattern.
Too slack and the cam will not rotate enough to operate the selector, thus not operating kickdown.
Correct adjustment is vital to good health and operation of the box.

Crossplies replied........

You've explained it very well and I've learned something about the transmission which I never knew.This has always been an unknown area to me as apart from cleaning the box filter and changing the fluid, I've left it alone.....until now! I've just been for a drive and I don't think the kickdown is working.I have the original box with 59k on the clock.The box has never been worked on nor adjusted. All changes are smooth and take place at the right time so I guess the adjustment needs tightening so as to operate that cam and act on the valve body as you explained. A quick look at the w/m tells me that neither of the two adjustment methods is practical for me so I will have to leave it at the moment. I suppose all the kickdown does is save the bother of moving the selector to gain the extra acceleration. That's not a problem with D to 2 but could be more tricky moving from D to 1. At least the default seems to be for the adjustment to be too loose as I could see a problem if the downshift cable was too tight.

[harvey]

Personally I'd fit the support housing into the case before fitting the tailshaft.

And I'd coat the inside of the band with ATF as well when that goes in.

[eightofthem (Andy)]

Personally I'd fit the support housing into the case before fitting the tailshaft.

And I'd coat the inside of the band with ATF as well when that goes in.
[/quote]

Good points there Harvey, where have you been bud?, I have been missing your input.

Crossplies hang on in there I will get to the kick down cable eventually, and I will try to elaborate more on the matter.
Yours may well be seized in its sleeve.