interisting problem on a jcb junker

ericlb · Oct 18, 2012

the plant finally found a pigeon, i mean a person to give a couple hundred scrap for a old jcb commercial backhoe that crawled on the place decades ago, so rough it doesnt even have a model decal visible, but its a normal size backhoe this was a auction buy, i understand, and was cheap, real cheap, lol its sat for many years but still will run when it was ran they always worked on it more than they ran it, you get the idea.. whats interesting is the one of the many problems it has, it can't be driven more than a 1/4 mile or so then the right brake locks up, with absolutely no input from the operator to the controls,thats umm annoying to say the least, one then has to block the tractor, and loosen the brake bleeder and it will release the guys never have figured that out , any ideas? just curious

Joe IRL · Oct 18, 2012

can you post a photo of the axle. JCB used skid units from other manufacturers depending on the age of your machine. if somebody can identify the axle maybe you can post your problem in the relevant forum.

oj · Oct 18, 2012

JCB used either Ford or Leyland skid units for the backhoes... if it is a leyland skid unit the might still be a brass plate on the right hand side framerail at the front of the egine (underneth the fuel pump).
The brake problem sounds like a bad master cylinder... sounds like it's leaking into the brake line ... might have a bad brake line rubber hose too, they can colapse internally that stops the brakes being released.

showcrop · Oct 18, 2012

No help with your problem, but it reminds me of one of our town's fire trucks. It is a military surplus deuce and a half, that would slowly build up air pressure to the brakes. It kind of slowed responses to calls when you had to stop and crawl under and release pressure. Complaining about that and other similar issues greatly annoyed the chief.

glennster · Oct 18, 2012

see if there is a rubber brake line in the system on that side. if so, when the brake locks up, loosen the fitting closest to the master cyl on the rubber line, and check for pressure. if not bad, loosen the line on the other end, toward the brake actuator. possibly the line has collapsed internally.

Eldo case · Oct 18, 2012

Check brake pedal adjustment. I don't know if JCB uses rubber cab or platform mounts but if wore it could be moving enough to apply brakes. If adjustment is tight enough brakes won't relieve. Just like having foot on pedal. Would be a cheap fix. Let us know what you find.

NCWayne · Oct 18, 2012

Worked on an early 70's Ford cab over truck some years back with the same problem. In that instance it was a matter of the push rod from the brake to the master cyliner being just a touch too long. Turns out someone had lost/broke the one that was supposed to be in it and home made a new one. Being about 1/32 to 1/16 too long, if the peddle didn't return all the way to the bump stop, and stay here, the piston would partially block the release port. After a couple of times hitting the peddle to slow the truck, but not to actually stop, the brake would lock up. Once locked it would stay that way until it was given a few minutes to bleed off on it's own through the tiny bit of return port left open, or you crawled under and bled it at the wheel. Funny thing is after hitting the bump stop hard a few times, everything would sometimes work right as the rubber bumper would compress just enough to let the port be open enough to work, but without those hard hits it would screw up. Took a while to figure out what was going on with this whole problem but in the end a new, factory push rod solved the problem.

Anonymous-0 · Oct 18, 2012

Junk Comes from Britain, Nuff said!

Anonymous-0 · Oct 18, 2012

They used Perkins too.

interisting problem on a jcb junker

ericlb

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Joe IRL

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oj

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showcrop

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glennster

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Eldo case

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NCWayne

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Anonymous-0

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Anonymous-0

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