1985 Cat 931B wet brake adjustment

SN: 29Y01769 My 931B has wet brakes/clutches. My manuel only shows dry brake procedure (the one with the support bolt underneath). My question is are the procedures the same for wet or dry? Seems I have to press the pedals to the floor to make it turn. If I tighten the brakes to where it turns good, the brakes start dragging in 2nd gear (maybe I just don't notice in 1st). The rollers on the clutch release valves are good and clutch release pressure is 390 so I believe it is just brake adjustment. Thanks

What is the reference of the manual you are using.? SENR5334.?

Attached the OEM Manual. Maybe it might be a little more clear.

Thanks Nige, I will give that a try.

Nige, just to verify, will that work for my machine, I believe mine is about a 1985 model?

All service information is based on machine Serial Number, not model year. The information I uploaded earlier is what is listed for your Serial Number therefore, in the absence of any information to the contrary, I believe it to be correct. YMMV. There are other setting/adjustment procedures but all of them are for the dry brake setup with the support bolt underneath the brake band. I also found the attached after another search that may help.

I think the adjustment is the same for wet or dry but with wet it's very important that the bands aren't too tight when the brakes aren't applied. They will wear into the brake drums. A former Cat foreman who sadly passed away a few years ago (Bob/Ont) told me an easier way to adjust the brakes than measuring all the linkage. It should be in the archives on here but basically you remove the pin on the long rods that goes to the "humps" on each side of the final drive case. They should have a hairclip on the pin. Then tighten the brake bands snug. Not super tight just snug. Then shorten the linkage as much as possible that the pin on the long rods can be put back in. Then you loosen the brake bands to get the freeplay and set the pedal height for engagement. This guarantees that the free play is at the brake bands and not in the linkage. I think you loosen the brake bands 12 clicks or about 3-3.5 turns. Better to have more freeplay than not enough. Machine should coast to a stop when adjusted properly or roll on a slight incline. Should only need light foot pressure to turn. Both pedals pushed half way or so should stop machine and coast the same as if you shifted to neutral while moving. A little firmer on the pedals should apply the brakes.

I appreciate the reply very much. I will certainly look at that. I may get a chance in the next few days. Thanks

Look under 931B brake adjustment. You may have to loosen the brake bands 4 turns. You don't want them dragging.

I looked at the brake adjustments a little, but I may have a different issue. Let me give a little history : Bought about 3 years ago Would barely steer because of flat rollers (replaced and worked good) I have always had to press hard on the pedals. Last month I replaced the track chains, and while I had it on blocks, I noticed that when pressing the pedal to get full travel on the clutch spool, neither side will disengage. The brake will stop the track. When in gear both pedals pressed half way, machine starts to move at about half throttle. Pressure is 380 coming out of the clutch release valve (I didn't have the right size fitting to measure at the plug in front of the sprocket, so I measured right before it goed to the clutch case) I ended up taking both clutch case covers off. When I move the clutch release cam (with my hand) the release piston in the case pushes the yoke out all the way to the stop but the tracks keep turning. Both sides the same. While driving with one pedal half way, the machine still makes a slow turn, but it's like the clutches are not fully released, therefore more brake required during turns. So, my way of thinking (no expert) is the clutches should 100% disengage.

IMO the clutch on either side ought to completely disengage at some point as the pedal is going down before the brake is fully applied. Maybe the attached document might give you some direction on how the power train is supposed to work and how to test/troubleshoot it.

My only thought is in the old days when you had steering leavers and brake pedals I believe the operator manual said you got a gradual turn by just pulling the steering leaver and a sharper turn by applying brakes also the clutch may be fully released but I’m sure you would get some amount of drive because of the oil between the plates and discs

I guess that would be my question is how much drive should I have. Seems off that is enough to move the machine, but I just don't know. I belive it's been doing this ever since I've had it, I just always thought the brakes were weak. Wasn't until I had it on blocks that I noticed full disengagement still moved the tracks. But it may indeed be proper operation.

I’m wondering when we did oil clutch conversion on old 931s you had to bend the yoke possibly some one changed clutch’s and has a miss match also there is a measurement for the stop bolt you could check

I didn't know the yoke had to be modified for the conversion. When I had the clutch case covers off I did look at the stop bolt, the book called for 8mm. It was hard to measure it where it is located but it is close.

I wonder if with wet brakes there's still some friction from the oil that the sprockets/tracks could still move some with the clutches released when up on blocks/no load? I only mention it because a good way to tell if your clutch is good on a dirt bike is the back wheel will turn in neutral when the bike is on a stand idling. It will turn a little faster with more throttle too. Also when putting in new clutch plates it's important to fully soak all the clutch plates in oil before installing them. If you don't your clutch won't work until they're wet enough. Can be a little scary when you pull the clutch and it doesn't do anything. I had it happen once when an experienced Honda mechanic who didn't normally work on dirt bikes offered to do my clutch in exchange for some skid steer work. Went to a race and had to do half a lap in practice before I had a clutch. The worst part is the mechanic said there were more loads of dirt to spread than he thought so cancelled our arrangement without telling me. I didn't care if I had to spread 6 loads instead if 4. I was there anyway. To make it worse he filled out a work order and charged me full retail price for parts and labour. The owner of the shop was a good friend and had no problem if a mechanic did some outside work on his own time. It really ticked me off because I thought we had a deal. Then when my clutch didn't work I thought it was ruined and I'd have to do it again. I hate when people make a deal with you and then back out!

Thanks for the info. While I had the case covers off I wish I would have adjusted the stop bolt to get more travel of the yoke to see what it would do, but I was worried about causing problems. That would be the only fix, apart from something being internally wrong with the clutch pack. I adjusted the brakes like you mentioned, and I still have to really press the pedal to make it turn. (Been like this since I've had it) There has been a few times after a brake adjustment, I think I had them dragging a bit, then only a light touch of the pedal would lock the brake and turn great. I was worried they were heating from dragging, so I backed them back off to where I press hard. Then the tracks don't come to a sudden stop with brake applied, but a gradual stop as I'm standing on the pedal. That's how I have been using it.

Especially with wet brakes you shouldn't need much pressure to stop the tracks from turning. I'd look more into the steering clutches to make sure they're fully releasing. If they aren't the machine will power through them and keep going straight. My dry brakes don't need much pressure at all to stop the tracks. Yours should be at least as easy.

I guess I may take the case covers off some time and adjust the yoke stop bolt. Other than that it has to be internal and I don't see myself pulling it out to inspect it. If more yoke travel doesn't fully disengage it I will probably just keep using it as is

I'm not so sure the stop bolt adjustment is the problem.