Detailing Differential Questions

[MGD72Monte]

I'm looking to sandblast the rear differential so I can make it look good and I need to remove the brake backing plates to fix the metal wear of the bottom shoe contact area. I have the diff out of the car, the upper control arm bushing are out. I'm not sure where to go from here. There is nothing mechanically wrong with this diff. Can I just empty the whole thing, remove the yoke, axles, carrier so I can properly clean, sandblast and paint, then just reassemble it "easily" without having to change bearings, adjusting backlash, using marking compound, etc... I know I will have to replace seals but don't want to spend waste $$$$ on bearings and other stuff since there is nothing wrong with this diff.

 

Anyone out there with experience on this?

 

Thanks

[Grease]

When removing the ring gear carrier be certain to keep the bearing caps and shim/spacers to there correct sides . Mark both carrier bearing caps , so they are reinstalled back to the same side and same side up . I use a center punch . One dot top side left , two dots top side right .

For the pinion shaft you really should have a new lock nut and new crush sleeve to set the bearing preload . It can be done with the old parts but not recommended . Hopefully you will get some more input on this from others here as well .

[cny first gen 71]

My question is why do you need to take it completly apart. just clean it up and sand blast it all together then you can replace or repair the backing plates. Just make sure you clean the sand out of the tight areas (pinion and axles) if you pull the axles to change the backing plates change the axel seals

[MGD72Monte]

Thanks guys.

 

Steve, this might sound odd, but I actually did not think about leaving is assembled for the initial clean and sandblast , I suppose I'm used to thinking complete overhaul, taking everything apart then cleaning, painting and reassembling. I guess sometimes it takes someone with an external perspective to point out that there is an easier way. Before I disassemble any further, I'll start cleaning and then get my hands on the auto club sandblaster to see how sandblasting it as a complete unit goes. If that works well, I will then only remove the axles so I can refurbish the backing plates, change the seals and reassemble.

 

I'll keep you guys posted.

[V8Freak]

im doing one right now, and im a detail freak. the most logical way i did it was I removed the drums and all the break hardware, left the backing plate on and diff cover. But make sure you duck tape the axel seals, wheel studs, pinion and especially the vent tube!! i was going to rip mine apart too but if you leave one grain of sand in there it could mean a catastrophy

[wallaby]

The pads on the backing plates where the brake shoes rub aren't that critical. You want to have them smooth and without gouges or burrs so the brake shoes don't get hung up when they travel, but that's about it. We used to clean them up with a small disk sander, or in extreme cases deep grooves could be filled with a little brazing before reshaping with the sander. It wasn't hard to do and it was all done without removing the plates.

 

I get nervous when using a sandblaster. I used one years ago to to strip down an old military generator that had maybe 20 coats of bad paint on it. Without doubt, the paint came right off...but sand got EVERYWHERE. I had taped off the control panel area and avoided going close to that area when I blasted, but sand found its way into the backside of the gauges and left a layer of sand in the faces of the gauges that was visible when I removed the tape. It's just an example; you can figure that anything that gets in the same room with a sandblaster is going to be eposed to grit small and large even if it's taped.

 

I'm not trying to talk you into cutting corners or not doing things the right way...just letting you know the process is messy and the cleanup afterwards is the hardest part of the job.

[MGD72Monte]

Thanks Mark,

 

When my car had some restoration work done in a shop years ago it had the same layer of dust behind the instrument panel lens issue so I know sand can be a problem.

 

In the past used a sandblaster on many individual pieces and I like it because it does a much better job than wire brushing. In this case I will make sure to triple tape the seal areas and vent tube.

 

On the backing plate pads, thanks for the extra info. I wondered how perfect they had to be. Some of the bottom ones have some groves I think need to be touched up, not sure if they would cause binding yet, but since I'm in there I'll see what I can get my hands on (i.e. MIG or brazing).