Trouble with rubber boot on trailing arm

[grapeman!]

Anyone else having trouble with the rubber boot on the trailing arm not staying connected? On my bike, the front of the rubber boot disconnects from the front side of the trailing arm. If you pull it back a little you can see the drive shaft. Also working it back in place only lasts a little while before it pops out again. Looks like another warranty job unless I can figure out how to get it to stay?

[famousperson]

Yes, I have trouble with that boot which disconnects at the front on my bike, also. The service manager at my dealer said it doesn't matter if that area is left open. I hardly believe that. Why have a boot if it doesn't protect something; esthetics, maybe? On the other hand, why would he shrug his shoulders since he'd get paid for fixing it?

[Lost Rider]

I had that problem with mine. Until I was able to see/play it, with the FD completely off the bike.
There's a hard plastic oval ring insert in both ends of the boot, be sure that it is seated properly (and not cracked) , and when you're pushing the boot back on try and stick your finger in the ribbed part, closest to the shaft and seat it from the "inside" part going around it the best you can. picture the hard plastic ring in there and try to get it jammed in the arm the best you can.
This has worked for me, along with a liberal amount of BMW grease.

BTW, mine gets pretty dirty in there leading me to believe BMW didn't really care about sealing this part of the FD and the boot is more to look good and make it dust resistant, not sealed IMO. If it was imperative that it was sealed they would have made it sealed...

-Joe

[grapeman!]

^ Yeah that is it. ^

I talked with the dealer today. They said they would order the parts and to set up an appointment to get is fixed. According to the service manager it would be a 30 minute job. He told me I could continue to ride the bike but should get fixed.

[Lost Rider]

^ Yeah that is it. ^

I talked with the dealer today. They said they would order the parts and to set up an appointment to get is fixed. According to the service manager it would be a 30 minute job. He told me I could continue to ride the bike but should get fixed.

Yes that's it, like that's the part in the picture i was talking about, that part is broken, or that's what wrong, and I can't get it to seat?

I'm just wondering what the dealer is going to replace? In other words is it common for this inner ring to break, or is your dealer able to use The Force to know what parts to order without even seeing the bike?
I'm interested either way, if you don't mind following up....

[grapeman!]

Yeah sure no problem, I will post the outcome.

[hjsbmw]

Are there any other insights how to do a DIY fix for this rubber boot issue?
I realized last weekend when cleaning the bike that the same rubber boot came off at the same location, i.e the front side where it connects to the swing arm. This morning I saw it was off again. I can push it back on, feeling a noticeable 'click' but maybe the plastic ring that's supposed to hold it is weak. It was not broken when I did the fd oil change in November '09.
I can't see how getting dust, sand, or water in there would not matter.

[Mollygrubber]

Mine was popped off when I arrived home after the first service. Didn't think much of it, just jammed it back on and it stayed.

Seems to be holding OK, but I'd better look at it also.

Peter

[famousperson]

Mine was popped off when I arrived home after the first service. Didn't think much of it, just jammed it back on and it stayed.

Seems to be holding OK, but I'd better look at it also.

Peter

Me, too. My dealer wouldn't fix it saying there wasn't anything in there that that could be hurt. ??

Peter

[73516]

Right from the get go my kept sliding back, not completely separating. The dealer in Grand Rapids Mi. replaced both the boot and the connectors under warranty. The new one fits great

[deilenberger]

IMHO - The most common cause of the boot not staying in place (and this isn't that obvious) is the plastic locking ring that fits inside it gets cracked (perhaps just does it, or perhaps due to mishandling.) It's worth examining the ring REALLY closely next time it pops out (and IMHO, that can only be done with the rear-drive dropped down as is required to drain the oil on the '07-08 models..) I found it easiest to check by removing the boot and then examining the plastic ring.

Unfortunately - REALOEM doesn't show this as a seperate part, so if it's broken, it's either glue/epoxy it, or pay $80+ for a new boot. I don't think the boot design is good enough to keep water out of the area if the rear end is submerged (Chitown?) but it should keep rain and general munge out of the area if the boot is properly installed.

[famousperson]

Don,

Is what my dealer said true, that the boot doesn't cover anything critical? He wouldn't fix it under warranty and that's the reason he gave.

Also, a side question: i know there has been at least one thread on this, but at what milage should (must?) the rear drive oil be changed on an '07?

Thanks.

Peter

[hjsbmw]

I plan to drop the fd and take a good look. Does anybody know for sure if the oil (180ml) will stay below the ABS sensor opening when dropping the fd, or will it spill out? Can be easily solved with a plug but that would be another trip to get one.

Since I am at it, the recommendation to change the oil is every 12k miles.

Does the boot cover anything critical? It covers mainly a U-joint and the shaft splines, but also the shaft itself and the entries/seals to the transmission and final drive.

Edit: I just ordered the part from Lynchburg BMW for $65 shipped. The desire to get it done right the first time and not waste time unnecessarily won. The manual specifies to use "high temperature assembly grease" on the mating surfaces. Would lithium grease be a bad choice?

[deilenberger]

To answer - is anything critical under the boot? Well, it isn't an area I'd like to see packed with sand, or even water borne mud. The splines are there and the universal is there. The splines probably won't be destroyed unless immersed in mud/water since they really don't slide much if any. The grease in them should keep contaminants out. The universal is a sealed unit.

I'd rather see it dry in there and clean, but I wouldn't panic if some dirt got in - your automobiles driveshaft has the same sort of splines/universals (provided you have a 4WD or RWD car) running with basically no protection.

[NakedRider]

Also, a side question: i know there has been at least one thread on this, but at what milage should (must?) the rear drive oil be changed on an '07?

Thanks.

Peter

It should be changed at the initial 600 mile service and every 12,000 miles after that.

BTW the cover everyone is talking about is just a dust cover. Just the same I would re-seat it to keep things out. The only damage I've ever heard of was from the San Jose BMW racing team with Brian Parriott on board. They picked up a rock in theirs. Of course theirs had no cover at all.