I thought my BW35 had a serious problem

[Barten]

Yesterday I took my nice original 3500 1971 out for a spin. The roads were dry and the it was nice to try out the new Vitesse Wheels properly. I stopped for a Meeting car just before turning into my drive. When I started up I heard a bang, then grumbling noises from the gearbox. I got a few meters of progress so I was off the main road. In neutral it was OK to push it, and my wife and I was able to push it back to my father inlaw's garage. It made grumbling noises in all settings except neutral and park if I push it forward as far as it goes. Maybe it Works in reverse, havent tried that. I have been under the car, but could not see anything particular. I took 3 Pictures showing the lever being in Park, Drive and then 1st.
What can it be?



Regards, Barten

 

[harveyp6]

Re: My BW35 has got a serious problem

Does the speedometer register a speed when in forward drive? If so it's not the box it's the diff, and so don't put it in PARK otherwise you'll snap the pawl off. If the speedo doesn't register then it probably is something inside the box.

 

[Barten]

Re: My BW35 has got a serious problem

Thanks for quick reply. I went out an checked, and the speedo is showing 20- 30 kph when i put it in Drive. So that is a differential rebuild then? Hopefully easier than the gearbox.
regards, Barten

 

[harveyp6]

Re: My BW35 has got a serious problem

That's the more common failure point. To confirm it the prop should turn with the handbrake on. Usual problem is one or other of the output shafts. You can put a scrwedriver into the oil filler hole to lock the diff unit, if the prop still turns it's the diff input shaft broken, which can happen but is rare in my experience, knowing which output shaft has failed is far more difficult. I had a pretty good success rate getting the right one, but the worst way is you'll end up pulling both. Hardest job is getting the broken bit out of the diff gear.

 

[Barten]

Re: My BW35 has got a serious problem

Maybe the easiest route out of it is to find a good replacement diff then?
Any way I need to get it off the car and can then do some checking on it. I would like to expand my experience also, and to see the internals of the diff should be fun!
I guess the general condition of the internals should decide whether I will rebuild it or go for a good used one.
regards, Barten

 

[harveyp6]

Re: My BW35 has got a serious problem

I always repair them in-situ, but it's your call.

 

[Barten]

Re: My BW35 has got a serious problem

Maybe i would do that if I had a lift, but I don't. I will start tomorrow.
Regards, Barten

 

[harveyp6]

Re: My BW35 has got a serious problem

I've never used a lift. If you can jack them up high enough to do a set of pads, then you can strip the diff.

 

[Barten]

Re: My BW35 has got a serious problem

I will give it a try then. I take it you think it is just one of the axles that has snapped. Can I also check the conditions of the bearings doing it in-situ? I might have to ask you a lot of stupid questions, Harvey.
Regards, Barten

 

[harveyp6]

Re: My BW35 has got a serious problem

Check with a screwdriver in the filler hole to make sure it's not the pinion shaft, then you will have to guess which output shaft it is, which can be done, but is tricky, it's a matter of feel. Then remove the driveshaft and disc, followed by the caliper pivot pin, and the 4 bolts that hold the output shaft housing. You'll soon know if you have the right one. If not remove the other side.
You need special puller plates to remove the collars to get at the output shaft bearings if you want to do those, but the collars are supposed to be one use only, so they can be ground off. You can usually feel if the bearings are OK, and they don't give many problems.
Once you have the broken shaft out we'll move on from there.

 

[Barten]

Re: My BW35 has got a serious problem

Thanks Harvey. It will be an intersting day tomorrow!
Regards Barten

 

[Barten]

Re: My BW35 has got a serious problem

Busy day yesterday. I did the checks Harvey recommended and ruled out that the forward shaft was broken. I tried to take out one of the driveshaft in situ,but after struggling to get out one of the pivot pins from the caliper and seeing that there was quite an oil leak from the forwards shaft, I thought what the heck, I remove the whole thing. I have recenctly installed the diff in my project car, so this went fairly smooth. A big jack and the wife helped a lot.
Laid it on the bench, took off the calipers and drained the dirty oil. The LHS shaft felt dodgy so I took that off first. Not a pretty sight. Lots of metal swarf in there.
What will be the next step after this? Do I have to split open the diff to get out the remains and clean out the swarf? I guess that is the right thing to do, but I dont know how complicated it will be.



regards, Barten

 

[SydneyRoverP6B]

Re: My BW35 has got a serious problem

Hi Barten,

Opening the diff as you say would appear the only way forward, else you could never be sure that all of the metal has been removed.

Out of curiosity, how many miles were on your diff, and did you break traction when going around corners etc? From my understanding, that is really the only way to destroy axles, like what we see with yours.

Ron.

 

[Barten]

Re: My BW35 has got a serious problem

Hi Ron,
The brown Rover has only done 90000 km and no brutal take offs since I got it in 2005. I have however got the kickdown to function by doing some adjustments to the throttle likages and the kickdown cable, but surely it is supposed to be able to kick down!
There has been a bearing noise in it this year however. I have suspected wheel bearings, but checking them myself and by mechanics I thrust, nothing was found wrong with the fron wheel bearings. The big ball bearing on the LHS shaft did feel knackered now, not very surprising I think.
Regards, Barten

 

[SydneyRoverP6B]

Re: My BW35 has got a serious problem

Appreciate the info Barten. Seems that the damage was done then prior to your ownership. Using kickdown won't break the diff drive shafts like we see with yours.

The diff in my Rover now has over 315,000 Miles on it, (507,000km), and remains all original. Up until 2007, I would use kickdown quite regularly, as the original 3.5 litre engine would benefit from such behaviour in terms of acceleration. When the 4.6 was installed in July that year, the need disappeared. I have always been mindful to minimise the possiblity of breaking traction, as doing so places considerable stress on the drive shafts, not whilst traction is lost, but when the tyre grips and traction is regained.

Ron.

 

[harveyp6]

Re: My BW35 has got a serious problem

That diff looks to have had a hard life at some time. One or other of those shafts was destined to break. Two replacements required.

You can unbolt the N/S of the casing, and then lift out the crownwheel and diff assembly. Once it's out you can clean everything, and get the broken bit of shaft out of the planet gear. Most of the time you can pull it out with a magnet.

 

[Barten]

Re: My BW35 has got a serious problem

Yes, it looks like the other shaft also has had it. I took it all apart today. In my opinion, the damage was concentrated to the driveshafts and there were some scouring in the bore where the breakage happened as seen in one of the pictures below.
I tried to pull off the thrust collar to get out the bearing on the LHS. The puller was not strong enough, I tried to heat it up as well, but that didn't work either. I will have to cut it it seems. The shafts are scrap anyway.
I guess I should try to get hold of seals, bearings and rebuild the diff as best I can. I found 2 thrust collars in my spares stash. I have wondered what they were! Look a bit complicated when reading about it in the manual, but easier when I get my hands dirty.



I will set up a mail to Wins tonight and ask if he has got all I need for the rebuild. He has surprised me positively before.
Regards, Barten

 

[Barten]

Re: My BW35 has got a serious problem

I made a film Clip while I was wiggling the drives seen in the Picture. Unfortunately I am not able to lous up the Movie Clip, so you can't hear the clicking sounds it make. I assume it need a little bit of slack to avoid being too tight when it heats up?
There are a lot of shims involved but I don't know here to start if I have to to something about it. The wear on the drives doesn't look to bad to me, no marks seen on them, just even wear. If anyone can tell me how load up mivie Clips, I'll do it.

 

[harveyp6]

Re: My BW35 has got a serious problem

I think you've dismantled way beyond the point that you needed to, and if you hadn't detected any problems previous to the shaft snapping, and you can't see anything blatently obvious as a problem now, then I'd reassemble it exactly as it was.

 

[Barten]

Re: My BW35 has got a serious problem

Thanks Harvey. I gues you are right in that I have a tendency to go over the top and then thing sometimes get complicated. On the other hand, This time I could have just changed the broken shaft, and then the other side would probably have broken quite soon.
Whether I shall change both the diff bearing is questionable, I think when I have it all open, I 'll do it as a precaution. The shaft bearings I will definitely change. The one on the broken side was not good.
But I will leave the rest of it as is. Your diagnose was very correct though, and saved me a lot of trouble. I could have been dismantling the BW35 now if it was not for your advise. Thanks!
There was one thing I did not understand in your second post to me : "and so don't put it in PARK otherwise you'll snap the pawl off"
What is the pawl? I did put it in park before that post, so what could have happened?
Regards, Barten