1974 931 caterpillar track loader rebuilding Right side track tensioner

[Mikestowing]

Hello first time post. I am slowly getting a 931 thats been in my family for 40 years up and going sn 78u1674(6s3600) I Just recently ran it and the track tensioner on the right side gave into age. Im seeing seal kits on the internet that look like its a nylon seal and an outer nylon wiper.
Question 1 Are there any additional seals I will need for this?
I also havent taken all the guards off yet so Im assuming the chrome track tensioner rod has probably succumb to age remembering over 20 years ago the left side had the same issue with chrome flaking and rust.
Question 2. Where do you recommend sourcing these parts and im looking for reasonable prices and some decent quality but this is a hobby machine
Question 3. Im looking for the exact procedure on performing this job. I believe Ive spotted the master link that has a dimple in that particular pin
Question 4. While unrelated Im looking for a proper brake adjusting procedure the left side seems to need a bit more mashing than the right it is for sure disengaging the clutch but Ive read through the forums and I have located the adjustment on the rods to the brake housing but dont know if this is the proper adjustment point.
Question 5. Maybe the most important question but I need a service manual on this machine Im very handy and have a repair shop but Im just now getting fully aquinted with this piece of equipment mechanically. I need a reliable source whether digitally or paper dont care which.

 

[Nige]

Maybe the most important question but I need a service manual on this machine

I can help you with that. The Cat Publication reference is REG01387. There seem to be quite a few advertised out there including this one on eBay.

I would also recommend getting yourself a Parts Manual, then you can search for both genuine and aftermarket parts using the same appropriate Part Number based on your machine Serial Number. The Cat Publication Ref is UEG0711S and it covers 78U machines from first built up to S/N 3913, which includes your machine. Hint: If you don't find a paper one online at a reasonable price this manual can be downloaded from the Cat web site for $124.

 

[Mikestowing]

Thank you. Any idea if there are any additional seals per the tensioner besides the ones Im seeing online? Just shows two.

 

[Nige]

The attached is all the Parts Manual shows.

If you have never been into one of these assemblies before then be warned that big spring is not known as the Death Spring for nothing. Be VERY careful how you work around it. You should not need to touch it but be aware of the power it has and check the condition of the hardware that secures it very carefully before you start undoing stuff.

 

[Welder Dave]

Adjusting the brakes is probably somewhat similar to a 931B. It's too long to type an easier way to adjust them again. Use the search function and look under D3C and D6C. I posted how to adjust the brakes in post 36 of that thread. Basically take off the brake arm to the brakes, tighten the brake bands, shorten the linkage as short as possible it can still be connected and then back the brake bands off to get proper pedal freeplay. This guarantees the freeplay is at the brakes and they aren't rubbing. Note that the steering valve(s) could be causing the problem either by themself or in conjuction with the brake adjustment.

As far as the track adjuster rods, you might be able to use an epoxy to build up pitted or damaged area's. Have heard of people doing this on hydraulic cylinders but don't know if I'd recommend it for that. The track adjusters though aren't as critical as the hydraulic cylinders. They just need to be smooth and seal. They won't contaminate anything else like bad hydraulic cylinders could. About the worst they could do is leak. Might be worth considering if the rods aren't totally shot. I used some rust converter on parts of the rods that were exposed. The chrome was still good where they sealed.