New output shaft seal failure/ clutch pushrod probs.

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Lurchio
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New output shaft seal failure/ clutch pushrod probs.

Postby Lurchio » Thu Aug 10, 2017 5:09 pm

Hello fellow fettlers,

Having just changed the clutch on my R1150rt, whilst the box was off I have changed both front and rear input shaft seals, the rear one had failed and caused a big leak which I caught just in time by the looks. (Did the modification to the housing as well!)

There was also a SLIGHT leak at the output shaft seal, so again as the box was off, changed that. All the seals, including the output shaft were carefully measured (vernier) in their installed position before removal as I knew this was important. They were removed using a screw in 'puller' which is essentially two sharp screws on a yoke. The screws go in the seal body and you pull it out. The seals were all replaced by drifting them in with the correct sized drift in every case to the same installed depth as the originals. The spline shafts were wrapped in ptfe tape and that was then oiled to prevent lip damage as the seal installed. Theres no burring on the shaft surfaces, and no movement in the bearings behind the seals.

I noticed that the replacement output shaft seal was different to the old one, there seemed to be a wider 'seal' area, with a correspondingly narrower 'hard plastic' housing area. The other seals for the 'box I had OEM from Madrid, the output shaft seal was out of stock, so I got that from Motorworks UK. A clue maybe?

Took the bike out for its shakedown today, after about 25 miles, stopped and got the smell of frying EP80/90! The output shaft boot was dripping oil onto the collector box, and was then dripping it onto the ground. The oil had also 'flung' back along the swingarm, and got as far as the inside of the tyre, so this is no small leak. Anyway, got the bike home and have removed the swingarm to examine everything.

The leakage is definitely under the output shaft seal, some has gone along the swingarm inner housing, but most has dripped out below, via the bellows. Theres definitely markings on the seal face where it sits around the shaft of rotation where the driveshaft U/J has lightly rotated against the seal face (theres a circle of moly that I lubed the spline with, its not a 'fling' but a circle right on the immediate seal lip area), even though the snap ring in the U/J and the installed depth of the seal are both correct. Theres no obvious damage to the seal, just this circular marking. Weird.

The seal looks okay, but obviously its not!

I have just pulled the seal, and can see a LOT of oil behind the seal housing. I can also see a oil feed in the top of the housing, this was clear and the seal I put in could not have obstructed it. The bearing behind has a fully sealed cage, but I can see a small hole in this, probably caused by the previous removal. (Didn't need to use a 'puller' to get the new seal out). Surely, this wouldn't cause this leak? There cannot be much pressure going on there, so high up the box. The breather is clear by the way.

Any ideas? Could the new type seal have to go in further? Does that hole in the bearing cage seal hold an answer? The hole in it is TINY, like the tip of a bradawl would make.

Thanks very much.
Last edited by Lurchio on Wed Aug 30, 2017 8:27 pm, edited 1 time in total.

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Re: New output shaft seal failure

Postby Mike D » Thu Aug 10, 2017 7:11 pm

The seals used in that application are the later Teflon lipped type. These need to have the lips formed then placed on a sleeve. There are a number of special BMW tools called for in the BMW Service manual that are used to achieve this and to then insert the seal. One set is for the crankshaft end seal and the for the clutch end seal.

Did you use the correct tools?

Mike

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Re: New output shaft seal failure

Postby Lurchio » Thu Aug 10, 2017 8:16 pm

Hi Mike,

I know the situation regarding the crankshaft seals, I have left mine alone as they were not leaking and I didn't have the tools to do that job anyway, I have the BMW manual and could see that the crank seals were a no no . Confirmed that the seals I changed on the gearbox were the usual vitron (or similar) lipped type, with an internal wire/spring around the inside of the sealing lips, not just the plain lip on the crank seals which needed forming and were NOT so fitted with this spring, so getting the 'give' in the Teflon spot on is essential.

In respect of the gearbox seals, the special tools consist of a sleeve and a drift. The sleeve I assume is to protect the seal from the output shaft splines whilst it is drifted in (I substituted this function with PTFE tape and oiled the surface), the sleeve may expand the seal, but the internal spring / wire would surely contract and re align when it hit the plain part of the shaft. Nowhere in the manual (or Haynes) does it emphasise the seals for the gearbox input/output shaft have to be preformed. I stand to be corrected of course.

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Re: New output shaft seal failure

Postby King Herald » Fri Aug 11, 2017 6:24 pm

If you pulled the seal out with no effort, then it was not in tight. Which means it could leak around the out edge. I assume it is like most rubber moulded oil seals, and the interference fit is what seals the outer edge against leakage. You could either try some silicon sealant, or try a different type seal.
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Re: New output shaft seal failure

Postby Lurchio » Mon Aug 14, 2017 9:36 pm

An update,

The seal looks okay, but theres definitely been some 'blow by' around the housing / seal flange. (Box is off AGAIN..... don't ask). Anyway, checked everything closely, there is a gouge in the gearbox housing where the seal sits. The seal outer will not 'reach' into this, so theres the cause of the leak. Even though I was really careful, it seems that either the drill I used for a pilot hole for the puller, or the pullers screw its self has caused the gouge, which goes all the way into the housing from the outer edge of the flange to the bottom of the housing and is about 1.5mm wide by 1mm deep. Sod it!

Any ideas? I am loathed to use ordinary silicone,I thought JB weld, but the gouge is so small it may not take, and also may expand at a different rate in use and fall away. I have ordered OEM seals, but could do with this being the last time............ Thanks in advance.

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Re: New output shaft seal failure

Postby Jaythro » Tue Aug 15, 2017 1:40 pm

Use an RTV sealer lightly on the outside

We have to do this when building airhead boxes and using the new "diapraghm" seals

we use a dab of RTV to seal the inverted V at 12 o'clock (The old type rubber seals used to slightly deform into it and seal it)

My Favourite is the Cyclo Grey gasket sealer on all the bikes I build LINK
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Re: New output shaft seal failure

Postby Lurchio » Tue Aug 15, 2017 3:08 pm

Jaythro,

Thanks for your time and trouble in answering including sending the link! I will go with that then.

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Re: New output shaft seal failure

Postby Boxer11002198 » Thu Aug 24, 2017 4:57 am

Jaythro,

Thanks for your time and trouble in answering including sending the link! I will go with that then.
Hi Lurchio.
Intrigued to know how you are getting on ?
R1100RT 1996 19000miles Fom new at purchase .Now 24000 @9 th July.
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BMW K1100RS 1995 Sold
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Re: New output shaft seal failure

Postby Lurchio » Fri Aug 25, 2017 12:13 pm

Shw'mae,

Got the oem BMW seals from Madrid, and used high temp RTV sealant around the edges of them all and some on the area of slight damage within the output/input shaft housings. All good at the moment. The extended spline clutch disc I fitted is reassuring, and theres definitely a more 'robust' feel when taking up drive etc. Its not my imagination or auto suggestion, it feels more 'solid' if that's the right thing to say! Anyway, the riding season re starts in September after the August lay off due to heat down here, so will keep you updated as it goes.

Hwyl,

Ian

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Re: New output shaft seal failure

Postby Mike D » Fri Aug 25, 2017 12:40 pm

+1 on Feedback on the revised clutch plate - that would be much appreciated.

Mike

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Clutch pushrod probs

Postby Lurchio » Mon Aug 28, 2017 8:10 pm

Following a 150 mile 'shakedown', I have checked for any further leaks, and can report its looking really good. I pulled the clutch slave to check the rear input shaft seal / slave seals I changed, again looking good. One thing, I pulled the clutch pushrod to check the felt / rod just to confirm all was okay, had a hell of a tug to get it out. After checking all was okay (it was) went to put it back in, and found that at about the stage that the far end of the pushrod passes through the spring plate of the clutch assembly (and thereafter the rear of the crankshaft I assume) it was impossible to get it in with hand pressure. I used a little more leverage (NOT excessive) on the 'slave' end of the pushrod against the cross tube mounting of the gearbox and it went in to its normal position. I could then pull it out easily, and replace it to its normal installed position by hand. I seem to remember it was a bit awkward to insert after I replaced the gearbox previously.

It is NOT bent in any way after levering, and turns normally inside the input shaft. It will go in and out easily (now). Something has centralised I think (I did have it all centred up on installation, the box went on sweetly and I used the correct tool), Any thoughts on whats going on? Does the crank have a bush or something that needed the rod to be pushed into?
Last edited by Lurchio on Wed Aug 30, 2017 9:29 pm, edited 2 times in total.

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Clutch pushrod probs

Postby Lurchio » Wed Aug 30, 2017 8:25 pm

Hi all,

Any thoughts ?

For me, I think in removing and replacing the box (again) the centre plate of the main diaphragm spring moved making the hole mis align (again, slightly) with the crankshaft tunnel. When I replaced the box, the pushrod was out, as I didn't want it hanging up or bending. When I tried to get it back in, the mis aligned holes showed up. Now, I am guessing the centre boss of the diaphragm spring 'floats' on the spring body, being attached by the three 'fingers' riveted to the inner onto the centre boss and floating by spring pressure against the spring body. When I nudged the pushrod with the lever, the end of the rod went in and aligned the centre boss with the crank tunnel, which looks like it has a 'funnel' at its entrance by the pics, so making it easier for me. Obviously the slave was out when I did this, so everything was in a normally assembled state, and not clutch engaged, etc.

The clutch was definitely aligned bang on when re fitting (from the last time!), the box went on easily, dowels etc., all correct.

The pushrod is definitely still straight, and now moves in and out easily in the hollow input shaft with two fingers, it rotates as it should. The clutch works fine with no strange noises on idle or up to 3000 revs in first gear.

I still have not installed the swingarm, etc. after checking, so interested to hear views before I button it all up and start bloody RIDING it instead of fixing it!

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Re: New output shaft seal failure/ clutch pushrod probs.

Postby King Herald » Thu Aug 31, 2017 6:26 pm

Oil in the hole it goes into, and now you pushed it in the oil has vacated the hole? I've never gone this far into one of those motors so just guessing really.

I can't imagine the clutch push rod actually contacts any of the rotating mass and holds/pushes it into alignment, like a clutch alignment tool does.
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Re: New output shaft seal failure/ clutch pushrod probs.

Postby Lurchio » Thu Aug 31, 2017 6:54 pm

Nice thought, but:

Theres no oil in the crankdrilling, as it's a dry clutch. Funnily enough the clutch pushrod is quite a good interference fit in the crank drilling, lots of people actually use it as a baseline centralizing tool with sockets etc for the clutch boss.

With the clutch lever in apply, it spins at engine revs, the crank end thrusted against the centre boss of the diaphram spring and rotating with it being centralised by the thinner end of the pushrod enclosed in the crank drilling, and at the slave end whizzing around with the small bearing set in the slave cylinder piston.

All good reasons I want to be happy before buttoning it up for hopefully the last time for a Long time!

Thank you anyway!

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Re: New output shaft seal failure/ clutch pushrod probs.

Postby sykospain » Thu Sep 07, 2017 3:04 pm

You seem to have done everything correctly when treating this sod of a dry clutch, Lurchio.

Mechanics supervisor son Tim says his team use the slave pushrod as a centring tool, 'coz different vintage Beemers need differently-sized clutch plate alignment dowel tools, so for the hydrau-clutch 6-speeders they use the pushrod to centre the clutch pack, assisted by the "optical alignment tool" - i.e. rack o'th' ee. Viewing the equal and correct spacing between the edge of the friction plate around the circumference of the pressure plate.

And putting a dab of Staburags - only Klüber Lubricants 'Staburags' NBU 30 PTM paste and not Honda Moly nor any other lubricant - on the tip of the rod and also smearing its angled shoulder where it bears constantly throughout the life of the bike against the diaphragm plate. It's the special insanely-waterproof, ultra-high-pressure lube that you toothbrush into the gearbox-input-shaft splines when you have the bike in halves. Only a pea-sized blob is needed for that, too.

Individual bikers can get it in a little 20 gramme tube like an underarm deodorant roll-on sized format, not a tin. Tim's workshop big-tub of the stuff costs 600+ snoojits.

His other pro-tip is NEVER to pull up the gearbox-&-tranny assy onto the bell-housing with the bolts, when re-assembling the bike. He says if you have to pull the units together by tweaking the bell-housing bolts, there's summat wrong. Either something trapped between the interface, or incorrect alignment of the small dowels, the error you had on first reassembly, Lurch. Tim's lads always use the headless M8 long bolts as temporary alignment guides.
Incidentally, ¿ are you in Andalucía like me ?
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Re: New output shaft seal failure/ clutch pushrod probs.

Postby Lurchio » Thu Sep 07, 2017 4:49 pm

Hi,

Really appreciate all your time and trouble and yes, Andalucia. Granada province, near Baza.

Starburags used all the time on this job, a 20gr container as you said, on the splines and the places you mentioned, also the contact points on the clutch pack, promise you. The ONLY reason I nipped the box up on the bolts was that I was doing it on my own and I could see that the splines and dowels were all engaged and lined up, but the soddin top 'cotton reel' rubber mounts on the gearbox that goes into the bottom of the battery tray were fouling the underside of said tray and I had to slip the bolts in whilst I pryed at that horrible idea. So it was only the force of those fouling that was the prob for the last 10mm.Same issue the second time, again on my own. I used the headless m8 bolts as a guide, oiled as well. Made them up especially.

Interesting about the pushrod. I used the Motoworks tool and ensured it 'spun up' at all stages. As I got the extended spline plate from them, and had their tool I contacted them to check it would still function. They said Yes, and also added this to their website in relation to the tool.The tool I have is the MW one, specially for the r1150 six speeder, as I said checked loads of times during installation, spinning away nicely. Visual check, it looked spot on. (You can see the triangle created by the spring fingers rivets if you look down the clutch boss.

I think the clutch pushrod thing may have therefore happened when I was trying (grunting!) to install the box, and something happened to the spring centre plate, apparently its easy to disturb it.

I either put it all back together (I have dry run it up, and alls okay), or take the box off to check everything. I suppose I could get a new set of clutch bolts and do a refit as regards centralising through the starter motor housing and save getting the box off nothing better than the fitted input shaft and pushrod , just a thought!

The other thing I should mention is that as it now is, after nudging the pushrod in, when I activate the clutch, I have checked by removing the starter motor, the clutch disc is free and floats as normal with no play on the input shaft and the disc can be rotated (alright, pushed around with a small screwdriver on the edge!) the full 360 degrees with no tight spots or abnormal drag. It all points to being square!

Not enjoyed this job! Grrrrrrrrr! Why me????

Ian


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