931B track adjuster seal question?

I have a question about the track adjuster seal that is in the barrel. The seal goes against a steel ring. The seal has a flat side and a grooved side. Does the groove go against the steel ring or away from the steel ring? Thanks in advance.

The seal lip should be positioned so that the grease pressure in the track adjuster forces the lip against the shaft of the idler yoke. See attached. If by "Steel ring" you mean the bearing #39 then the lip of the seal should face away from it.

Nige said: The seal lip should be positioned so that the grease pressure in the track adjuster forces the lip against the shaft of the idler yoke. See attached. If by "Steel ring" you mean the bearing #39 then the lip of the seal should face away from it. Click to expand... Nige, thanks for the reply. So, if i understand you correctly the seal goes into the barrel with the lip facing away from the yoke. Which would mean the flat side of the seal goes against the steel ring? Correct me if I am wrong? Thanks

That's the way the diagram shows it, and to me it's the logical way because otherwise it wouldn't hold grease pressure.

Nige, thank you very much for the quick reply to my question.

Let me see if I can explain it a bit better. The illustration below is NOT from your tensioner but will serve to illustrate the point. Consider the grease pressure (blue arrow) being applied to seal #12. That pressure will tend to open the "V" in the LH side of the seal and hopefully prevent grease leaking past it. That's the blue seal in your photo. Now consider the wiper seal #13. If the shaft moves to the left (red arrow) the lip on the wiper seal should "wipe" any contamination off the rod and prevent dirt entering the tensioner cylinder. The wiper seal is the brown one in your photo. To me it sounds perfectly obvious because I know how it works. I hope it is the same for you.

Nige, thanks for the explanation and diagram. Seals are in and all put back together. Below pic of head wiper seal.

I've got a question.... I've got a 931B, and after new tracks the seals didn't "seal" too well. We took apart one yoke assembly, and it was pitted some towards the idler yoke. I got after it with a VERY light sander and knocked down any high spots of rust or other. Polished it up a bit (with higher grot sand paper) and once back together it worked just fine (held pressure). However, now the other side is NOT holding pressure when operating the machine. I'll be taking it apart and doing the same possibly next week. Is there a process to repair the polished part (now defunct from years of rust and decay) of the cylinder/ram without buying new? Sorry to hijack, but seems it falls inline with the seal(s) question.

I think you probably should just do what you did on the other side to fix it. Only other thing you could do is look for a shop that rechromes cylinder rods..

dirtworksequip931 said: I think you probably should just do what you did on the other side to fix it. Only other thing you could do is look for a shop that rechromes cylinder rods.. Click to expand... Agree.... but, not sure how long that'll last. Looking for ideas for the future.

Only other option is to have the rod rechromed. Or look for a parts machine that has better rods than what you have now.

dirtworksequip931 said: Only other option is to have the rod rechromed. Or look for a parts machine that has better rods than what you have now. Click to expand... It can be rechromed even if pitted and rusted away towards the yoke?

I would imagine that they would grind in it as smooth as they can and build up any low areas. Then turn it down to the correct diameter. Then rechrome it.

Track adjusters aren't as critical as the hydraulic cylinders. You won't contaminate the entire system if there's a slight leak. You might be able to use epoxy and sand it smooth for it to seal. Grease is thicker than oil. I used rust converter on the exposed part of the rods on my track adjusters. The rod was in decent enough shape where it had to seal. If the rods are really pitted there might be aftermarket rods available that would be cheaper than repairing the bad rods.

Welder Dave, great idea about using an epoxy on the rusted end of the cylinder. It would sure be worth a try.

dirtworksequip931 said: Welder Dave, great idea about using an epoxy on the rusted end of the cylinder. It would sure be worth a try. Click to expand... It would... But, you can't polish epoxy enough I'd think to allow a smooth gliding seal to work properly. I'd think the seal's friction would cause premature wear and grease to push past. Surely easier than anything else... to "try". I'm a hobbyist welder/fabricator... I could always spend some hours building it up, grinding smooth, sanding to a polish and keeping it relatively round and proper. I'm sure that would work too. Just be more time consuming. It's not like it's a vital cylinder ram... where it's moving like a curl bucket ram, or similar. It's very little, not very often. ... I myself have options, just cool to share and hear other's ideas

People have used epoxy to repair hydraulic cylinders. Don't think I'd do that but a track adjuster isn't as critical and there isn't the same amount of movement as a hyd. cylinder. I think epoxy could be polished with very fine sandpaper, 3000 grit if required. All the rust would need to be cleaned first. If there are several pits would be much more difficult to repair with welding and getting round and smooth. You'd also need to use stainless rods.