955L Right Brake Locks Intermittently. Why?

It's primarily the right brake that locks intermittently when in use. Just started doing it. I thought it was the debris built up causing the linkage to get stuck, but I don't think that's what's going on. The left has done it a few times also, but 9/10 times it's the right side. Fluid is clean. I changed 50 hours ago and checked earlier today. Suction screen should be clean also. Problem seems to go away fairly quickly, but then comes back after 1 min, or 20, just depends. I read that it may be caused by high hydraulic fluid pressure buildup, but I don't know how to fix this. I read it may be due to collapsed return line. This may be a possibility because the return line is leaking some, can't tell how much though. Tracks may be a little on the tight side. One of them gets loose occasionally so I put more grease in. I don't think I over did it too much, but could this be causing it? Any other ideas or fixes? Thanks

possibly the springs on parking brake paw broken or something pushing parking brake down?

It could be. I am going out in about an hour to work on it again, and I will have a very close look at the center brake mechanism. It seemed to be ok earlier, but I was more focused on the individual brakes and linkage.

Fluid level was actually low. I only checked fluid quality in the filter housing. The lower return line o ring had a crack in it. Will try to get a new hose tomorrow. Lost about 4-5 gallons without knowing it because it had been collecting in the belly pan. Hopefully no damage done. I think the lack of fluid was causing this. maybe air bubbles were increasing hydraulic pressure occasionally causing the bands to lock. Fluid looked brand new, so I think i'll be ok, but hopefully can get a new hose tomorrow, or at minimum I have new orings.

I think it might help you to know brakes have no hydraulic assist all mechanical. The only hydraulic involved is to release the steering clutch. my question to start is how much travel do you have in brake pedals If it's excessive the linkage might be going over center and causing the lockup

It's a custom hose only available from cat so I wasn't able to get one today, but the O-ring was where the major leak was coming from. I think air was getting pulled into the system and that's where the brakes locking up was from. The problem stopped after I put new o rings and the old hose back on, put fluid in, then ran the loader for an hour with the reservoir cap slightly off so the air can vent out. I am about to order a new hose. 7k2777 from Cat.

are your brakes adjusted too tight

rnexus said: I think air was getting pulled into the system and that's where the brakes locking up was from Click to expand... You need to read carefully what @pittsburgh cat man posted above, especially the part “brakes have no hydraulic assist, all mechanical” .

^^^ Agree Make sure the pedal is full up With a 9/16 Remove brake cover at rear of machine Tighten adjusting nut under cover until snug Now loosen nut 2.5 turns Reinstall cover

I think a 955 is 9 clicks from tight or a turn and a half so you have 3 inches of free play in pedal d 3 and 931 went 2 1/2

Your more right than me but not completely right It's 1 1/3 turns not clicks To get to that point there are several other things to do first