Porous BW 35 ?

[taz]

Tracked my transmission leak down, after initially thinking it was the sump gasket (replace it twice!) to what must be a hair line crack, otherwise a section in the casting has become porous - my leak is in the valley between the rear servo brake adjuster and where the filler meets the case. eg it's kinda a valley on the side of the transmission. Very hard to get too.

Is this a common fault? If so, what is the usual remedial action? I just slapped on some epoxy putty but I may be kindding my self with the kind of pressures internal to these boxes.

If I do end up removing the transmission and having it reconditioned, the chances are that the locals here will build it to the ford BW35 spec. Is this actually a bad thing?

And lastly, is it worth replacing the putty around the seal of the tunnel cover - if so, what do you recommend I use?

Thanks in adv,
Taz.

[Phil Nottingham]

I understand its not usual for the Servo housing to crack but not the main body - I would try out your putty method - you have nothing to lose. It must be completely clean though for it stick and if it is fluid under pressure I doubt that it work. I do not know what the difference is between the two specs Ford just had special requirements which Borg Warner accommodated - the rebuilders should know - I doubt its going to make much difference especially if that is the only choice. There were several various models of boxes used anyway throughout its life - the last one with none adjustable bands suposedly the best. Subject to using the right kickdown cable to suit the box/carb set-up they will all fit. What car year is yours?

Dum-Dum is the correct stuff but any non-setting sealent which is heat resitant will do. Its really essential as it prevents transmission of noise,dust and fumes

[taz]

Very helpful once again - many thanks Phil.

I have a 1971 model, P R N D 2 1 job. Kickdown cable is burried behind the air cleaner somewhere. I was going to put a guage on the pressure test port and look for the 15-20psi increase from 600 to 1000rpm thing.

cheers,
Taz.

[Phil Nottingham]

Yours has therefore the later type of kickdown cabe but not the latest of the boxes fitted which were only on late 72 's

[taz]

Well,
So much for my attempt at stopping the leak with epoxy putty...

It did not even slow the leak down
I doubt it's repairable - very hard to get at - and even harder now with my putty in the road!

[Roy of the Rovers]

Perhaps with the box removed it could be aluminium welded, ie just heated to remove any porocity? Otherwise (and more simply) get yourself a 2nd hand gearbox and get that one rebuilt. There should be lots of old P5b boxes knocking about

[stantondavies]

Epoxy putty would have done the trick if only you could have got the box oil-free, which is as easy as finding hen's teeth.
I've had a leaking box (with the car at rest) for fifteen years or more. I used to throw money at it, now I just collect the oil and use it to preserve the garden fence.

[Phil Nottingham]

Well at least you tried!

Its put up with it until you can fit a recon box - the band adjuster certainly looks like its had some use so perhaps its ready anyway?

[taz]

Thanks Folks,
I'd like to be able to grin and bear it, however the spillage pools are measured in feet not inches!

I dont like my chances of welding up the case either -I think these alloy castings are very soft and may be further annealled by the heat.

I think I will give it one last try - wash it with acid, a good rinse and a spray with brake cleaner then fill the whole area with putty - heaps of it, and see how that goes.

Otherwise, I read elsewhere on this forum of someone replacing the main case only with a ford BW45 (very common here in oz, as used in early falcons). eg use the rover torque converter and bell housing together with the rover rear extension.

Fingers crossed!

[glennr]

I know this sounds strange but would it help if you used a hairdryer to warm the area before applying the putty?

[Deleted]

We used to use an aluminium putty type product called DEVCON. it was pretty effective and could be machined, filed, drilled and threaded etc.

Cleanliness is the key and the secret to sucess, best of luck with it.

Cheers

Adrian

[stantondavies]

As it is a hairline crack, a smear of araldite might be another option? Still requires ultra-cleanliness. Epoxy putty remains my choice. Clean away and good luck.

[dorsetflyer]

The way that's leaking you have no hope in hell of curing it unless you can drain all the fluid out so there is no more leaking out. Then and only then should the area be thoroughly cleaned and all traces of fluid removed. Also roughen the area with either wire wool or emery cloth so there is something for the putty to key on. Then fingers crossed you can try the putty again.

Devcon is very effective, this product was developed for the Aerospace Industry, and we used it widely in the sixties, seventies and eighties. It's probably used still today.

[Allan NZ P5b]

www.devcon.com/index.cfm
here is their web site good tech data info.

Regards

[taz]

Thanks folks,
Dorsetflyer was right.. it didnt work. Whilst I think I got the area surgically clean, as soon as the epoxy-putty made contact it appeared to bring out more fliud - ie the fluid liked having the putty there as it improved it's 'wicking' mechanism.

The box had not been used for 5days, and whilst not empty, I know the oil level is way below where the crack is, however there must still be some oil under pressure behind the crack - and a lot of it! Not sure how to relieve it either.

I will start looking for another box. There are very few P5B's here in Perth so I dont like my chances there. I understand some P6B boxes will fit, and there are plenty of them here, the 303 XXX ones or something. And I can look into fitting a ford BW35 or 45 from a falcon.

Cheers,
Taz.

[gregwebb]

I fitted a BW 40 from an XF Falcon to a p5b using the rover bellhousing and extension housing/output shaft.
The advantages are the larger torque converter and geartrain etc
It is a relatively straight foward conversion

[taz]

thanks Gregwebb,

did your BW45 TC have the rover spiggot on it?

I've located a recon BW35 from an XB falcon (circa '74). However the front pump shaft is different necessitating the use of the Falcon TC as well. Which would be fine - ie it seems to fit, only it does not have the locating spiggot (that goes into the female hole in the flex-plate). I think the spiggot is only used to ensure the TC is centralised (ie no vibrations), but would'nt the gearbox pump shaft also tend to locate the TC centrally?
So do I really need the spiggot?

thanks in adv,
Taz.

[PatMcCoy]

I bought a spiggot for a auto gearbox £17.63 del from wadhams because the engine i bought was set up for a manual

[taz]

Sorry -
Spigot is probably not the correct term. What I'm referring to is the 3/4 inch shaft, about 1.5inches long that protrudes from the engine side of the torque converter, which slides into the flex-plate.
It's obviously for locating the converter before bolting it in, but it's not a very precise fit, so I dunno how well it would do at preventing vibrations anyway if the converter was screwed up slightly off center.
I can use the Falcon torque converter but the trade-off is that I will have to rely upon the gearbox front shaft (which the converter mates too) to ensure the converter is mounted exactly on the crankshalf axis.
Sound reasonable?

[Phil Nottingham]

Yes - if it works Ok

[gregwebb]

The XB Falcon converter should have the same 3/4 spigot boss as the orignal Rover converter if I remember correctly.
Has this converter been modified?
The spigot boss on the converter plays an important role in centralizing the converter to the flex plate and aligning the converter to the pump during assembly and would give extra support once fitted.
The XF converter that I fitted had a much larger spigot boss which I had modified when the converter was overhauled.
The bw 35 from the XB Falcon will have the longer extension housing, which means that the Rover output shaft and extension housing needs to be fitted thereby ensuring that the Rover prop shaft and mounting etc all fit.
If the bw 35 has a push in type kickdown cable the cable from a Rover p6b fitted with a bw 65 fits straight in.
Fitting the Bw 40 entails about the same amount of work with the benefit of another 12 to 13 years of improvements etc.

[Phil Nottingham]

The BW35 kickdown cable is screw in

[gregwebb]

The Australian produced bw 35's changed to push in kickdown cables sometime during the mid seventies. If the XB Falcon bw 35 has a screw in cable the P5b cable will screw straight in.

[taz]

Thanks Gregwebb - I'm not sure if the kickdown is push or pull? What do you think...


Also, the XB torque converter has an inverted cup for a spigot boss, about 40mm diameter, which I was simply going to remove with a hacksaw.
The drive (rear) shaft look considerably different. I havent ripped out the guts yet to see how different it is internally, however I'm beginning to doubt the rover shaft will be a direct swap.
I've also learnt that the XB falcon had a 2.92 diff ratio, so I suspect this BW35 may be setup for different gear changes.
Another headache is the filler tube - the one on the XB is completely different and the mount is via o-ring and I will have to try and machine the case to accept the P5B threaded union.
Since I dont have a big investment in this box, I'm wondering if I'm better off seeking a P6B (7FU,267,303) and overhaulling it, or as you suggest, seek a BW40 from an XF.
Was the rover drive shaft a direct replacement for BW40? And did you have any issues with the gear change speeds?

Thanks in Adv,
Taz.

[gregwebb]

Your kickdown cable is the screw in type, so just replace it with the p5b one.
The Rover output shaft and extension housing will fit but the transmission has to be dismantled to do so.
Your torque converter has the same large circular boss as the bw40 that I used.
I had the same issuse with the filler tube but I welded the end of the Falcon tube onto the Rover tube after cutting off the threaded section off the Rover filler tube.
I can't comment on the gearchange change points as my p5b is under going a major restoration (4 years so far) and therefore I haven't driven it on the road .However the gear changing seems fine whilst running the vehicle on stands.I understand the this isn't a conclusive test however.
Fitting a p6b transmission would best less hassle for sure.
I have previously fitted a p5b transmission into a p6b with no problems.
The main reason I fitted the bw 40 was that it has the bigger converter and gear train etc,considering that the bw 35 is about on the limits of its capacity in a p5b.