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Discussion Starter · #1 · (Edited)
Everything is apart for trans/clutch maintenance so thinking of fixing this while I am waiting for my rear shock to be rebuilt.

I have a few questions here:

1: Is there supposed to be slap in the FD input shaft? Or is this a sign of failing needle bearing or ax bearing? (It will move up/down slightly) Although never had any vibrations from the FD this concerned me when I was inspecting it.

2: Would the FD input seal be worth replacing while it is apart just to be safe that a seal has not been shredded by a failing bearing? (Feel like drilling a weep hole in the rubber boot for the sake of having a clean FD would be ignoring a potentially bigger issue here)

3: Anyone know somebody who can make me one of these (33 1 700 - PIN WRENCH)? Because I already know what should probably be done here, bike has 73k I bought with 26k and never touched any of this. It has leaked on top of the FD since day 1.

A few pics of the issue at hand.
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Hey Waldo, the first thing you need to determine is, where is the oil coming from. Oil pooling in the boot can come from the final drive seal or the transmission output shaft seal at the other end of the drive shaft. Check the swing arm for any signs of oil running down from up front. Even with removing the swing arm to get at it, the output shaft seal is easier than the pinion seal on the FD which requires some special non hardening thread sealant and some hefty jigs and tools to remove and replace the seal. The castle ring actually has the seal inside it and is tightened to 87 Ft Lb but the pinion nut is a whopping 147.5 Ft Lb. Here is a picture of the tools I made to rebuild my FD. The castle socket I welded additional metal to the tabs so they had a better bite. It was the only castle socket I could find so there might be a better fitting one that wouldn't need any modification. I welded up some angle iron to bolt the ring gear and housing together so I could get the 87 and 147 Ft Lb I needed while standing on it on the floor. If the bearing is smooth, I would not remove it as it requires a good bit of heat on the case to get it to release. I damaged the first one I removed and had to wait for a replacement to arrive.

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Discussion Starter · #3 ·
It is definitely coming from the FD input shaft side, I just removed the gearbox to fully rebuild for an input shaft failure and my output shaft seal was dry plus oil is pooling up under the driveshaft.

Looks like changing the seal is not possible then without removing everything. Guess I may as well rebuild ASAP then, as I can only assume this means a shaft bearing failure may be around the corner if oil is leaving the bearing enough to get past the seal. The last thing I need is to be stranded on the side of the road or worse yet, end up buying a used FD because the shaft gear eats my whole case if things go catastrophically it could definitely be both of those. I read one instance where the guy had a hole in the aluminum casing after that bearing failed and his gear sheered a few teeth off.

I read somewhere that the rear wheel can actually be used as a jig, bolted to the hub and securing the FD to the wheel with a strap to hold it in place. Anyone ever try this method? Seems too easy to be true but also worth a shot if it works, I'm growing tired of making special tools for what should be pretty simple tasks. Guess I need a Spindle Nut Socket and 36mm deep walled socket to make this happen then.

I will at least replace the seal and re-Loctite the crap out of it for the time being as my crown bearing does not seem rough and I can easily spin the input shaft with 2 fingers, no grinding noise with my ear pressed to the FD everything seems to be smooth and free of any binding. Perhaps this is just a faulty assembly job and not enough Loctite was used at the factory or the oil seal is old and worn maybe both. While I'm there it should be easy enough to see from the outside if the bearing is deforming somehow there might be more obvious signs under the seal that is, especially considering that shaft almost feels loose. Shouldn't it be solid in there? Is it possible the bearing has failed but not blown out completely causing the shaft to have a wobble that would not be noticeable riding? I will try to post a video of this.

Could someone point me in the direction of the best resource for a full FD rebuild, video or otherwise? Still have a few weeks down time waiting for my shock and a FD rebuild is most likely inevitable anyways, the way I ride this bike 15-20k/yr I will probably need a spare motor within 5 years at this rate so maybe ill just grab a used FD in a month or so and do that one the right way as time/money allows.
 

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My pinion shaft seal was leaking or so I thought which is why I pulled it apart but I found that the spindle nut was finger loose most likely from a previous disassembly where someone thought that Good N Tight was tight enough and did not use the proper torque specs. I would give that a check before you pull it totally apart, you may be able to just pull the castle nut and spindle nut and reassemble that. If you want the best in the business for a FD rebuild, that would be Saddleman and we can get you two in touch if you want to go that way. There are several other things you should look for if you are going to do it yourself and the measurement window for proper shim setup is about 4 thousandths of an inch. Dave does a full rebuild and gear setup and has the tools to do it right. Besides myself, I would not trust anyone else to do it for me.
 
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