U-Joint bearing replacement

[Rafael]

Has anybody replaced the U-Joint bearing with the swing arm still attached to the frame? The engine and trans are out of the way and I don't see any obstructions but the drive shaft is sloped relative to the floor. I haven't taken a Quota swing arm off before, so I'm not looking forward to it. In any case any tips would be greatly appreciated.

Thanks,

Rafael

 

[Rafael]

It turns out the answer is - YES.
I had bought a blind hole bearing puller from Harbor Freight to change wheel bearings. The large puller in the set was just large enough for this bearing, and the grippers just cleared the back plate that the bearing rests on. I disengaged the shock lever arm and leveled the swing arm in order to have enough space to operate the slide. The 3 pound slide did not generate enough force to move the bearing. So, I then removed the puller handle and stacked several large washers over U-joint housing and puller then extracted the bearing by turning the added nut. Since the puller in is concealed in the u-joint housing, I could not use a wrench to keep it from tuning, so I used a 16” inch slot screwdriver to engage the grippers from the rear drive end of the swing arm. The square shaft on the screwdriver allowed the use a wrench for adequate leverage. The screw driver was used for setting or removing the puller as well.

A threaded rod will be used to reseat the new bearing.

My tool chest is filling up with home made tools!

Cheers, Rafael

 

[Mike.C]

Excellent result eh! Love the homemade tools, adds to the satisfactio of a job achieved.

 

[john zibell]

The thing to think about are the swing arm bearings. If they are tapered roller bearings, it is a good idea to grease them occasionally which means take the swing arm out. If sealed ball bearings, then by all means, don't remove the swing arm if there is no lateral play. Can anyone confirm the type of bearing? The part list doesn't say if it is tapered roller or sealed ball bearing.

 

[Rafael]

thanks John, I'll check with MG Cycle about the sealed or roller type bearing. No lateral play was found but now that I have the new U-Joint bearing I did find that there is slop between the U-joint and the inner race. Is this a big deal? The U-joint is otherwise still in good shape. Any Recommendations?

 

[john zibell]

thanks John, I'll check with MG Cycle about the sealed or roller type bearing. No lateral play was found but now that I have the new U-Joint bearing I did find that there is slop between the U-joint and the inner race. Is this a big deal? The U-joint is otherwise still in good shape. Any Recommendations?

Yes that is a problem. It should be a slip fit into the race. Try four equally spaced center punch hits to the end of the cardan joint that slips into the carrier. These punch points should be half way between the end of the joint and the first u-joint on the shiny part of the assembly. Then refit the cardan to the carrier bearing. If it won't go, a little light filing at the punch points. If there is still slop, hit those points again. Get the idea?

 

[Rafael]

thanks, got it.
I'm wondering, since the other end of the u-joint is the same, except for the outside diameter, is it safe to have the mating surface machined to match the original diameter of the worn end? The u-joint would end up spinning in reverse of the original rotation. Not sure if there an issue. I may also have a problem finding a machinist that will be able to accomplish the work. -thanks

 

[john zibell]

thanks, got it.
I'm wondering, since the other end of the u-joint is the same, except for the outside diameter, is it safe to have the mating surface machined to match the original diameter of the worn end? The u-joint would end up spinning in reverse of the original rotation. Not sure if there an issue. I may also have a problem finding a machinist that will be able to accomplish the work. -thanks

Rafael,

See if the large end will fit in the carrier bearing. On later bikes the big end goes in the carrier and the smaller tapered end goes to the transmission.

 

[Rafael]

It seems that the big end mates with the transmission on older models. The big end does not fit into the bearing race. I'm hoping to machine the big end to fit into the bearing race.

 

[Rafael]

I found a local machine shop that specializes in drive shafts. The machinist turned the large end down to fit the bearing snuggly, minimal material was removed, but he could not cut the the spot where the mating surface meets the spider carrier (90 degree angle) very well, so the end of the u-joint is about 1.5 mm short of where it's suppose to be at the shaft side of the bearing. I don't think this will be a problem since the output shaft on the trans has more that enough length for the u-joint to sit forward by 1.5 mm.

John: Do you normally use Loctite in the bearing race to keep the u-joint from spinning in the race? I read about this years ago but I haven't done it. -thanks.

 

[john zibell]

Rafael,

I don't use any bearing or sleeve retainer on the carrier bearing. If you had a really loose fit, maybe, but if you have the slip fit I wouldn't use it. It makes removal of the cardan too difficult later.

 

[Rafael]

Re: U-Joint bearing replacement & U-joint

Well my buddy wasn't comfortable with the modified U-joint so he decided to go with a new unit. We found the Stein-Dinse u-joint kit at MG Cycle for a good price. Well, we thought everything would be straight forward from there, but S-D made an improvement to the design that make sense but make the installation more difficult. They reduced the tolerance between the UJ and the inner bearing race. The instructions (English found on line) called for heating the swing arm and freezing the UJ. It didn't work; probably because the tolerance for each unit was too close with the temperatures listed in the instructions. The tolerances would have been on opposite ends of allowable spectrum for this work. So it’s a crap shoot. We had the same shop turn down the UJ a bit -oops went too far. Not bad though, but the tight fit was gone. We decided, even though that I never had this bearing crack before, the German idea may be worth something. So we used sleeve retainer to lock the UJ in. We'll pay the piper later.... Hopefully 50k miles later.

 

[Penis Rotor]

First up the swingarm bearings are tapered rollers and are worth prying the seals out of and cleaning and re-greasing from time to time.

Secondly with the newer UJ's I leave them in the freezer overnight and then heat the swingarm up by, in summer leaving it in the sun for an hour or two or in winter leaving it on top of a hot car engine. The UJ can usually be aligned by feel well enough to get it started in the bearing and then it can be tapped home with a dead blow hammer. If it won't line up square you can stick the driveshaft and sleeve on the back toke and then lins it up by fiddling with the shaft from underneath the end of the upright swingarm.

Pete

 

[Rafael]

Thanks Pete, We did get the grease in at the swingarm bearings!

One other detail that I forgot for follow up on the thread is that I was unable to use the threaded rod and washers to install the UJ bearing. The bearing was hard to get started; the washer would slide to the side and out of square. I figured I needed a cylinder with the OD to match the OD of the bearing and the ID to match the OD of the threaded rod. This should keep the pressing surface square to the axis of the bearing. Making this piece would have cost more that having the DriveLine, the local machinist press it in for me. Cost only $15.00.

Back to the UJ: Per the poorly translated German instructions, we had the swingarm plumb and supported on a counter, used the drive shaft and sleeve with wood dowel pressed in for extra reach and grip, to guide the UJ into place. The UJ was in the freezer for a couple of days (in a plastic bag, wife didn't notice!) and the swingarm (no sun that day) in the oven for an hour to warm up to the recommended temp. We just could not get it started to the point that we felt comfortable that it was square. The instructions were not clear about tapping it in place, so we chickened out. We were at it for a while and afraid of ruining the UJ and bearing. Also, we thought that whacking the UJ in would only cause the UJ to squirm laterally. I thought that if we had a jig to hold the UJ to remain in line and not squirm then tapping it home would work. I suspect that the UJ and bearing are not matched as a set, so the tolerance can vary from .00 to .04 mm. Anyway, I'll have an opinion on witch method, sleeve retainer or friction fit, of retaining the UJ is best when we take this puppy out, if we can...