bevel box

[ciderman gs]

after draining the bevel box oil the drain plug was yet again full of bits i had changed the big bearing 4000mls earlier after a failed big bearing (28000) so i stripped the box off and found play in the input shaft after a phone call to steptoe (who was busy but still gave me 5 mins (thanks)), i had trouble breaking the input shaft nut 36mm 200nm and the oil seal/bearing preload collar 160nm so i took it to the local main stealer who said they where happy to break the nut and retainer, after 2 days i went back and they refused to repair the drive and suggested that i buy another one 2nd hand as it would cost too much to repair and they did not want to warrant the repair as it had chewed up a big bearing in such a short time so there must be something wrong with it.

to repair the bevel box you need:-

1 big battery/ air impact wrench 36mm deep socket and bmw special tool for the oil seal retainer

2 old wheel bolts

3 a good blind bearing puller

4 a gas torch with a very controllable flame for heating (soft enough for heating to harsh a flame will burn your paint HEAT GUNS DO NOT WORK ON THIS AREA

5 prussian blue for checking gear mesh

i have now replaced all the bearings and the gear mesh is right by the book the bearing that had failed was the needle roller at the end of the input shaft and this is where all the bits were coming from.

the workshop manual states that if you are not replacing the gear set then you need to check the measurements but as a foot note bmw uk do not stock any input shaft shims so a straight bearing replacement is in the realms of the home mechanic

 

[sockpuppet]

Could also use your oven to heat the piece up.

 

[Steptoe]

Could also use your oven to heat the piece up.

You've obviously never done the job that that ciderman is talking about

 

[sockpuppet]

I'm guessing its too large for the oven then...dammit. Seemed like a good idea.

I wonder if you could BBQ it instead.

 

[(RIP) Bin Ridin]

cue a "What Sauce do you use?" thread......

 

[Steptoe]

I'm guessing its too large for the oven then...dammit. Seemed like a good idea.

.

It's not too large - but you only need a small area heated up, not the whole lot.

It's pointless heating the whole lot, because everything will have expanded instead of the part you need to remove, so you'll be in the same boat as before it was heated.

 

[ciderman gs]

like steptoe says you need to heat the aluminium casing quickly and locally so as not to get heat transfer or as little as possible to the steel parts as the aluminium expands at a greater rate than the steel. also when putting the various bearings back on and in the casting and the input shaft

put the input shaft in the freezer for 1hr then heat the bearings with a heat gun for 5mins so you can touch it with gloves on 50-100c bearing expands through heat shaft has contracted through cold warm bearing slides on to cold shaft then when everything returns to temp bearing fitted without hammering. the only thing is you have to do it quickly as heat transfers very quickly.

also now i have run it the gear changing is better because of reduced backlash in the bevel box

 

[sockpuppet]

It's not too large - but you only need a small area heated up, not the whole lot.

It's pointless heating the whole lot, because everything will have expanded instead of the part you need to remove, so you'll be in the same boat as before it was heated.

Ah I thought he was heating up the bearings to get them to fit back.

Though I do like the idea of BBQ bearings.

 

[Steptoe]

Ah I thought he was heating up the bearings to get them to fit back.

.

I'll post how to heat up bearings and cases without using the oven using a specific tool perfect for the garage and very cheap.