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Drive shaft boot CLAMPS

lmo1131

New member
Just got the /5 up again after a Final Drive rebuild by Ted Porter and ran up a hundred miles yesterday; it was great.

But this morning I was greeted with a quarter-sized ($US) hypoid puddle that seems to be coming from the aft clamp ... I tightened these clamps (new ones) until I was afeared they might either break (at the screw) or cut the boot; it was still possible to tighten them further ( I just didn't).

"Oben" is properly positioned "up" and I put 140cc of oil in the shaft, so I don't think it's overfilled. The boot, forward of the aft clamp, is dry underneath.

I going to do a Simple Green wipe-down, apply some talc, and go for another ride later.

??? > Any comments on "how tight" is tight enough on these clamps? It's not like you can put a torque wrench on them.

??? > Is the clocking of the "joint" on these clamps (I have them both "up") critical? :dunno
 
The clamps are designed to clamp evenly around the housing. ...under the treaded screw is a little lip that is tacked to the clamp, Some times they break off and become missing. Make sure it is still attached. It's also easy to punch a small hole in the rubber boot. If the boot is old, it can become some what old and brittle and can split and leak. I think the boot is also handed. One is round to go over the transmission output and the other end is more oval to go over the driveshaft housing. The clamp needs to go evenly around both ends. I' ts easy for the clamp to slip off the boot a little and not seal properly. Just some things to check.
 
Thx barry, that was quick!

The boot is new, and it is handed... one end is circular (to fit over the cylindrical transmission flange), the other end is more "rectangular" (for lack of a better term) that fits over the swing arm tube.

I have it properly installed.

Checked Snobum's site for references about tightening these clamps, but found none.... tightening a band clamp is such a simple process.... usually. :brow
 
I recently installed a new boot as part of my clutch overhaul. I made sure the boot was positioned properly, both up and tranny side. I also had a small drop of oil on the ground after the first ride. Inspection revealed that I had not tightened the rear clamp enough. I wouldn't say that I "strangled" it but I made sure it was tight. Also, that's a pretty complicated area with the round part of the flange being welded to the crosstube of the swingarm, so you have a number of surfaces coming together. Make sure the clamp/boot is sitting where it should be.

Tighten it up, clean it up, and try another test ride. Mine stopped leaking once I got it tight.
 
It's NOT the purpose of the boot to contain oil--just to keep out dirt.

The problem is a leaking seal elsewhere.
 
Too tight on those clamps is when the clamp band starts to twist rather than the screw just moving smoothly through the threads.

Just got the /5 up again after a Final Drive rebuild by Ted Porter and ran up a hundred miles yesterday; it was great.

But this morning I was greeted with a quarter-sized ($US) hypoid puddle that seems to be coming from the aft clamp ... I tightened these clamps (new ones) until I was afeared they might either break (at the screw) or cut the boot; it was still possible to tighten them further ( I just didn't).

"Oben" is properly positioned "up" and I put 140cc of oil in the shaft, so I don't think it's overfilled. The boot, forward of the aft clamp, is dry underneath.

I going to do a Simple Green wipe-down, apply some talc, and go for another ride later.

??? > Any comments on "how tight" is tight enough on these clamps? It's not like you can put a torque wrench on them.

??? > Is the clocking of the "joint" on these clamps (I have them both "up") critical? :dunno
 
Lmo,

It may not be the clamp at all. Look very closely on the upper and lower side of the final drive housing near the end at the boot attachment. There may be a very small "L" tab spot welded to the housing at the top and bottom. It's very easy to overlook (if in fact you have these tabs on your housing) and accidently position the rubber boot over the tabs instead of sliding the boot under the tabs. You may have to look very closely or even reach in carefully and feel for them. There's also a possibility they may be pushed closed. If so, open them up with a small screwdriver blade. The boot and clamp should be positioned under these tabs. See the attached photos with yellow circles.

This "might" be what's happening with your boot. And, maybe not.

Here's a photo of the upper tab...

-Mike V. / San Diego
 

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Here's a photo of the lower tab, a bit tough to see.

-Mike V. / San Diego
 

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Thanks Mike... my swing arm definitely does not have these tabs... would have been nice if it had... an easy fix. I'm just wondering how many different configurations of swing arms the MutterSchiff built... . :dunno

BTW, busy conducting "bidness" today... didn't have time to wrench on the Rad. Definitely tomorrow....

Interesting... I have the screw/joints positioned at the top

edit- what camera/lens combo are you shooting with? Nice shots!
 
the screw placement

I have never seen the screw fastening joint at the top or the bottom of the boot. Doesn't it always go together at the right side of the boot?
 
Doesn't it always go together at the right side of the boot?

Good question!

Drum roll please.. .. . . :lurk


BTW, my "leak" stopped on it's own. Must be out of oil, huh?
icon_wink.gif
 
Mike,

What year is your bike? I have three LWB swing arms and none of them have the two tabs you show.

My little leak returned yesterday after a three hour cruise. I should say, two or three drops were on the shop floor this morning, and traced to the swing-arm boot clamp. I'm pretty sure I know why now... I had the clamp-joint in the 12:00 position and the screw "tabs" were colliding with the cross member on the sub-frame and slightly deformed. :banghead

I also noticed that the mold parting line on the boot is located vertically (12 and 6 o'clock). I've been involved in plastics molding for many years, and on a hunch, I peeled the boot back to take a look at the inside surface of the boot. At the 6:00 position there is a slight mis-match in the surface of the rubber, basically creating a tiny V-groove in the rubber; not much, but perhaps enough. I re-oriented my clamp to put the screw-joint at the bottom to help flatten this area out a bit.

BTW, I do not believe this is an OEM replacement boot. I have my suspicions.... there is no clear "BMW" logo, the molded in part numbers and "Oben" are not distinct, and then there is the mis-matched tooling...

I have never seen the screw fastening joint at the top or the bottom of the boot. Doesn't it always go together at the right side of the boot?

Sounds like a good POLE question to me.
 
Lmo,

The pictures I displayed are from my 81 R65. I don't believe these tabs exist on earlier model housings, I can't remember seeing them on my 78 R100/7 but thought it would be worth mentioning and I can't tell you what year they started showing up. But it almost tripped me up during the final assembly of the R65 restoration which is why I went to the trouble back then of the close-up photos.

And about the clamp positioning; personally I can't remember seeing them in any other position than the bottom. And in my mind, if the correct overlapping clamps are used it shouldn't matter in my opinion.

All of the boots I have experience with were OEM and the "Oben" is placed at the top. Another thing to look out for is a small manufactured pin hole. Maybe a vent hole? Obviously, if you have a boot with this pin hole it needs to be positioned at the top.

I'll have to go back into my notes and double check on things - I'm writing from memory. But I understand your frustration due to the asymetrical shape of the housing end. You might try to clean the boot very well, take a run and dust it to track it down. I agree these boots don't carry a lot of fluid in them but hypoid does exist in them and will find it's way on the floor without an adequate seal.

Let us know if you get this solved. In the mean time I think I may have a spare boot in the shop some place. I'll look for it and do some inspection.
 
I think my new OEM boot had both Oben and something like Getreibe on it to indicate which side went towards the transmission.
 
My little leak returned yesterday ...

That's because it never stopped because your problem is a leaking seal.

The boots are NOT there to contain oil.

The SYMPTOM is oil is leaking past the boots.

The DISEASE is a seal has failed.

Treat the disease
 
Installing a drive shaft rubber boot

I had my clutch splines lubed last week. Yesterday I noticed a split in the boot that is about 2" long. Surely a mechanic would have noticed that split as it was reinstalled. How could such a split happen---in removing it as part of the spline lube job?

I can't say that the split was always there --I never noticed.

So, if the mechanic put it back with knowing the split was there I'm not very happy. But who can say he knew??


At any rate I just ordered a new boot and it looks like I am facing a job very much like disassembly for lubinng the splines---right? If so can someone direct me to an idiot proodf step by step bvecause I think I'd just like to do it myself.

Thanks for any advice--a little sympathy would also be appreciated.
 
no where near as scarey as spline lubing...

You just need to remove the swing-arm/drive-shaft assembly. Truth be know, you don't actually need to remove it, you just need to move it back far enough to get the old boot off and the new one on. But being so close to having it off I'd remove it so you can clean that area on the drive-shaft where the boot seats...

1) remove battery - I found it to be much easier if the battery is removed, it allows a lot more access to the rear of the transmission.
2) place trans in 1st gear (to keep drive-shaft from rotating), loosen clamps on boot, loosen/remove drive shaft bolts (4 - 12pt.)
3) remove shocks
4) pull swing-arm pivot pins; you will probably need the "shaved-down" socket wrench to get the locking nuts loose... although if your mechanic re-installed a ripped boot, there's a pretty good chance he botched properly re-installing the swing arm, and the lock nuts may not be too tight...
5) remove drive-shaft

6) clean and inspect

7) install new boot on drive-shaft bell before reinstalling drive-shaft

the bitchy part is getting the drive-shaft flange realigned with the output flange on the transmission - it just takes some time, and patience.

8) install NEW, short, 12 pt. drive-shaft bolts - clean the output flange bolt holes with brake cleaner, acetone, etc. and use Blue Loctite on the bolts. Note that the boot has "oben" embossed on it, and that the two ends are of different shape - it is fairly obvious which way the boot goes on, but "oben" must be pointed "up"

Once the "mechanics" are hooked up it's just a matter of fighting the boot into position on the trans bell. I ended up making an "L" tool out of 1/8" welding rod (rounded off the end so it wouldn't damage the new boot) to help maneuver the boot onto the transmission housing.

9) reinstall and center the swing-arm.

Now as far as my "leak" goes... . the drips were coming from the drive-shaft end of the boot; the shape of the drive-shaft bell is irregular, as opposed to round (like the transmission end).

There was nothing wrong with any other component on the machine. It was simply a matter of not taking my time to carefully position the new boot on the drive-shaft bell. I hate crawling around on the floor (I don't have a lift) and as a result I took the easy way out and did not get down on the floor and eyeball the installation as I proceeded through it the first time.

I tightened the d-s end clamp enough to hold the boot in position but just loose enough that I could re-position it as required to get it parallel with the "face" on the drive-shaft bell.

I then tightened it further., and checked for any "bunching" rubber, or the clamp trying to cut into the rubber, and then finished tightening.

The third time was a charm... yeah, it took ME three tries.

Notes:

Do not apply any oil to the boot to help ease it onto the drive-shaft bell... it just makes it easier for the rubber to squirm around.

I purchased the torque wrench adapter from Northwoods, but it would not fit with the U-joint configuration that I have - I torqued the bolts using the rag-over-the-wrench-tug-till-it-hurts method with the little BMW 12pt box-wrench that is in my toolroll. That was almost 3,000 miles ago, and no problems.

If you want the silly torque wrench adapter, PM me and it's yours... it's completely worthless to me...
 
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