BW35 strip and rebuild in pictures

[eightofthem (Andy)]

OK HERE WE GO AGAIN.
TIME TO START TAKING THINGS APART, AND LOOKING AT WHAT NEEDS REPLACING.
STARTING AT THE FRONT, THE OIL PUMP IS THE FIRST VICTIM.

YOU NEED TO LOOSEN OFF THE FIVE 1/2 INCH BOLTS A LITTLE ( NOT ALL THE WAY JUST THREE TURNS EACH ).
THEN REMOVE THE SINGLE SLOTTED LOCATION SCREW.



THEN TAP EACH ONE OF THE FIVE BOLTS IN TURN TO LOOSEN THE HOUSING OUT OF THE STATOR SUPPORT ( IT IS A TIGHT FIT DUE TO THE SEAL )



WHEN THE OIL PUMP IS LOOSE ENOUGH, REMOVE THE FIVE REMAINING BOLTS, AND REMOVE THE OIL PUMP BODY.



MARK THE POSITION OF THE OIL PUMP GEARS BEFORE YOU REMOVE THEM.



THEN GIVE IT ALL A GOOD CLEAN SO YOU CAN GIVE IT THE ONCE OVER.



THIS IS THE SEAL ON THE OIL PUMP.




THEN YOU NEED TO CHECK ALL THE GEARS, BUSHINGS,AND HOUSINGS FOR ANY WEAR. ( THERE ARE FOUR BUSHES IN TOTAL THAT NEED LOOKING AT) WE WILL LOOK AT THOSE NEXT.
TEA UP.

[enigmas]

Andy when you decide to take a closer inspection of the planetary gears you need to check the endplay of each gear and also the condition of the thrust washers as well as the pins the gears ride on as these can wear significantly. This component is often overlooked during a rebuild, but if left it can and will fail cracking the annulus. (Ask me how I know?)

These gearboxes have covered huge mileages (given the age of the cars) and unless you know when the last rebuild occurred it would be false economy to neglect this vital component...The reference Harvey makes to needing certain specific tools is valid as although you can make the tool he referenced I would prefer to give the planetary set to a transmission rebuilder and have them do this particular component. Also ensure that the oil seals front and rear don't ride on any grooves (a speedy sleeve may be required here) There's nothing worse than a leaky rebuild! Enjoy

[harvey]

Feb 17, 2013 23:33:40 GMT enigmas said:

I would prefer to give the planetary set to a transmission rebuilder and have them do this particular component.

They won't do it, all they will do if yours is damaged is supply you with another one. Whether they tell you that, or tell you they've overhauled it is another matter. If you press the pins out and then try to refit them you'll never get a satisfactory result. It's a unit, and the individual parts are NSS.

[petervdvelde]

Andy,

Did you invite Cyf to come over to make some pictures or did he teach you? as these are very good

[eightofthem (Andy)]

All good stuff there boys keep it coming.

I made a list of all the parts needed to rebuild the box beforhand, just to make it easier for me to photograph as i go.



Ok we were at the oil pump, and the bushings were next to be removed.
The first bush to come out is the front pump bush, it has some hard wear, and is scored very badly.




You can see the difference when you compere it with a new one.




You can either press the bush out, or you can use the old socket and threaded bar method, or you could use a vice as a press. BE CAREFUL, these bushes are very soft and can be damaged real easy. Take your time and make sure they go in square and true.
The old one out.


And the new one in.




Next one to come out is the stator tube or input shaft bearing. This one has had a hard life too.
Dont be tempted to skip these, they dont cost much, and are not that difficult to replace.
I found a dremmel real handy on this, just be careful not to go all the way through the bearing and score the inside of the tube.



Same agian when it comes to fit the new one, press it in, make sure it goes in square





The next bush to come out is the one in the pump gear. If your gears are worn, then it might be already fitted in the new one, you will have to check that.
The gears are good on this one, but the bush is past it.



I used the vice on this one, along with the socket, and old wheel bearing race to press in and out.




Old one out



Old and new bearings together. The wear is evedent.



Press the new one in



There is also a forth bushing, at the back of the pump body, you can see it here in the center, this one looked good, so i was happy to leave it.




So that is about it for the pump. Give it all another good clean before you start to re assemble.


Fit a new seal to the housing.



Then get a nice big tub of vas. ( £1.00 from the pound shop bargain )




Pack the lot with it



Refit the pump gears and align the marks, then pack with vas.




Then you need to align these two holes and replace the two together ( this is where the little flat head screw locates )




Then loosely refit the screw.



Then refit the five 1/2 bolts, and tighten each of them in turns slowly. And then torque them up ( 17 to 22 lbs ft. ) Be careful not to trap the new seal.




Lastly, (well for me anyway). is the front oil seal. You could refit this earlier when it is stripped ( I forgot )




I used the old seal to tap it in. It has a shoulder that it buts down on to.




And it sits slightly proud, so dont be tempted to bash it flush.




So there we go. That is the first bit done. Next up is the forward, or front clutch, and input shaft, along with the front brake band.
Cup of tea beckons me thinks.

[johnwp5bcoupe]

Hi Andy a cost breakdown would be interesting keep up the good info

[eightofthem (Andy)]

Yes when it is all done, I shall break it down costs wise.
Trouble is all rebuilds will vary, due to what needs replacing. The worse it is inside the more it will cost you.
It is turning into a bit of a saga this.

[cyf]

Peter, I was not involved at any time in this saga!! Andy do it very well on it's own.
It's the type of thread that makes you want to get an old box to strip it down tomorrow!
I don't forget that it's Andy who encourage me to go on the engine rebuild

[eightofthem (Andy)]

Thanks for the comments boys, if all this helps just one person to have a go at their own box then it has been worth it.
If you have a sort of understanding how the car works ( or should work ) then you will be better placed to fix it, or look after it.

Ok next up was the front or forward clutch pack.



Firstly remove the thrust washer, and check it over. ( There are two thrust washers in the clutch pack, and both are available if damaged or worn. )


This one looks ok, if in doubt replace it.


Then remove the internal circlip.




And remove the input shaft.



On the under side of the input shaft is another bearing, look it over and if worn replace it.
This one is good.



Then lift out the clutch hub and thrust washer.


As before check out the thrust washer for wear, and check the hub for any damage.


Next there are five friction plates, and five steel plates in the hub, the frictions are all the same, and the very bottom steel is thicker and has a dish on the underside.
Remove them one by one, and keep them in order if you intend to re-use them.




Check out the friction plates for wear, you can see the friction material starting to break away from these. ( these dont cost much, so plan on replacing them )


And then check the steels for heat distortion, cracks, scoring, and blueing. These are flat steels so you can check they are flat too.


Here is the last one that sits on the diaphragm spring.



Under the last steel, you will find the diaphragm spring and steel ring.


There is another internal circlip holding the spring in place.
Remove it.


Then remove the spring, as you can see it is in many pieces.
It is supposed to be whole, but to find it broken is common ( thanks Harvey )


Then remove the steel ring. ( it is supposed to have a gap in it )


Next to come out is the piston located here.
It has two seals that keep it in place. You can either use compressed air to pop it out, by applying a jet of air.


Apply a jet of air here.
Be careful !
.

You can also remove it by giving it a good hard tap down on a flat soft surface, such as timber board, but as you will find out later compressed air would be very helpful.

Then remove the piston.


Here is the location of one seal. Leave it on until you are ready to replace it with a new one, as there are various sizes in the kit
.

Here is the other seal.


Check the the steel ball ( check valve ) is loose in the piston. Give it a shake, and listen for it rattling.




So there we go. Give everything a real good clean, check it all over for wear or damage, and then get ready to put it back together with new parts if required

.

[eightofthem (Andy)]

So now get ready to put it back together.
In reverse order. We will start here next time, probably in march as i have used , or i should say my girls have used most of my internet allowence for this month.




I have heard some say to soak the new friction plates in new transmission fliud, for my own ends i will replace dry, as my wife also uses the camera, and she is not a fan of sheds, or oil, or indeed anything mechanical

[harvey]

Personally I'd cover the frictions in fluid.

[Warwick]

Andy,

My gearbox is expected to land in the UK next week, and they expect to have it dropped off at your place a few days after it clears customs. If you don't bother with the photographic record do you think you could have it back to me for reinstallation over Easter?

[enigmas]

I'm with Harvey on this one. It's important to soak the friction discs in ATF. The actually friction material is very thin and 'burning' them by accident waiting for fluid to be pumped through the system and coat all the surfaces could be very disappointing! It's actually no different when fitting a rear or frnt main seal and forgetting to lubricate the 'rubbing surfaces. On first engine start-up the lip is burned off the seal and you have a permanent and annoying leak.

Good effort and great photos

[harvey]

Anyone care to have a stab at explaining why there are missing teeth on the plates?

[johnwp5bcoupe]

So has the Drum Harvey???

[harvey]

Feb 23, 2013 22:09:37 GMT johnwp5bcoupe said:

So has the Drum Harvey???

Yes, but not in the same places..... (In other words they don't have to be fitted in a particulat position in the drum).

[enigmas]

Mine are like that too...don't concern yourself with it.

[harvey]

Feb 24, 2013 3:36:59 GMT enigmas said:

Mine are like that too...don't concern yourself with it.

I wasn't suggesting there was anything amiss with that, only if anyone knew the reason why it was so. I thought that might have been you, but obviously not........ I must be the only one then...

[eightofthem (Andy)]

Hey up Warick, you can have this one if you like, I don't need it.
I might finish this one by Christmas the way I am going, so no chance of Easter for yours.
Besides, I am not the expert here, just the monkey.
Harvey is there a reason for the notches?.

[harvey]

Feb 24, 2013 19:57:58 GMT eightofthem (Andy) said:

Harvey is there a reason for the notches?.

Yep.

[Welsh Warlock]

Come on Harvey, you can't leave us in suspenders!

[eightofthem (Andy)]

Feb 23, 2013 20:57:19 GMT harvey said:

Anyone care to have a stab at explaining why there are missing teeth on the plates?

Go one then, will have a guess.
I think that early models had a clutch hub with these sections of teeth omitted for some reason, and when the box has been upgraded the hub was changed, but there was no need to replace the steels, as they would still work in the " new type hub ". .
Just a guess.

[harvey]

'fraid not...

[eightofthem (Andy)]

d**n thought i was on a winner there.
Ok then is it to identify front hub steels and rear hub steels, as the frictions are the same for both, but i remember you telling me that the rear are dished, and the front are flat ?

[harvey]

I didn't really think when I posted the question, that it would clutter up what is an otherwise clear and concise thread, so to avoid that continuing anyone who has any futher ideas send them to me via PM. Just think about what's going on inside there.