Gearbox shimming with solder wire

[B Murr]

Just a bit of idle curiosity here.

I've searched threads for shimming and cannot see anything obvious popping up about using solder wire or plasti gauge for shimming the gearbox. Has anyone any views on it, there must be some reason why people fork out for shimming plates when what seems like a cheap and usable alternative exists.

 

[cookie]

tricky to ensure the outer race doesn't tilt, i imagine.

 

[B Murr]

The procedure I was thinking of is here
http://jhau.maliwi.de/mot/gearbox.html

Looks like you could use solder wire or plasti gauge as in photo, fit gearbox cover and tighten down, remove and measure the depth of solder/plasti gauge

Photo of it is

 

[Beemerboff]

Just stuff and nonsense - the CORRECT clearance is measured at the inner race on an unloaded box and the pressure needed to crush the solder will change the reading by somewhere between 15 and 20 thou depending on the solder.
So if you aim for the old clearance of 0/ 4 thou you will end up with around 10 to 15 mm preload on the bearings.
Box will still work, but the life will be 2 to 5% of a properly shimmed box.

The factory has revised the clearance to 5 to 15 thou, but no one seems to care or believe, so it is probably not worth stating.

If you must set the bearings by crush get some of the correct wax measuring strip and a loose fitting spacer which replicates the bearing but slides easily on the shaft and in the housings without heat, as heat will melt the measuring wax.

Or just use the spacer and shim the box up until you can feel the tension, then go back 5 thou. A spacer is easily made by lightly grinding the ID and OD of a good bearing - usually one of the old ones will be good enough, but even if you have to buy one it is still a lot cheaper than a shim plate, parallels, depth gauge and micrometer if you have to buy them just for one box.

 

[cookie]

surely, using the bmw measuring plate, you are measuring to the outer race not the inner?


and when measuring the recess in the cover, that is where the outer race sits?

 

[B Murr]

Another interesting thread on this here http://www.advrider.com/forums/showthread.php?t=435511&page=4

Discusses use of mold a gauge, a type of clay that can be used instead of solder wire, plasti gauge will melt when heating the cover so that doesn't work. Impression I got from posts was that it is accurate, but that you have to bake the whole transmission to get it set which for most will not be practical as baking in your kitchen oven is going to stink the house out. Another poster there made up a bridge that they were able to use instead of a shim plate but it looked like a bit of a palaver making that up. The set up that mr farmer uses with a milled cover is also mentioned. The sense I get is that the mold a gauge http://www.cycleworks.net/index.php?main_page=product_info&cPath=29_33_52&products_id=344 approach will work, but for a £55 shimming plate and a depth gauge makes it easier. Although I can't help thinking that the bridge is worth more thought as it will be a lot simpler and cheaper to engineer than the shimming plate with it's precisely positioned holes.

 

[Rob Farmer]

I haven't got a milled cover. It's garyh with that setup.

 

[B Murr]

I haven't got a milled cover. It's garyh with that setup.

Sorry Rob, my mixup