All 4 brakes seem to be dragging. (1 Viewer)

badQtip

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91 HDJ81 1HDT. So I've been plagued by stuck brake calipers over the last year or so and now that all 4 have been replaced and about 10k miles put on with out issue it seems that all 4 brakes are dragging to the point of needing low range to move without skyrocketing the EGTS.

I parked it up gave it a look over and everything seems fine so I took it out for another drive thinking it was just one caliper locking up so I could identify it with the IR thermometer. After a lap around the block and a really hard brake peddle I took the temp of each wheel and fronts were dead even at 180F and the rears were 100F & the ambient temp is around 25F.

Possible causes?

1. Master cylinder sticking
2 Brake booster doing things it shouldn't
3. Vac pump also being a bastard

Anyone have a direction they can aim me?
 

David*BJ70

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Having had an almost identical problem on my BJ42, I put my money on the master. It is as if he does not release the pressure exerted on the calipers.

The only 2 solutions I had was either to wait (I'm not recalling (it was in 2007) ... say 2 or 3 hours) or unscrew a bleeder on one of the calipers to release the pressure.

Then, after a random time, the situation recurring.
 

Mtntopper

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Having had an almost identical problem on my BJ42, I put my money on the master. It is as if he does not release the pressure exerted on the calipers.

The only 2 solutions I had was either to wait (I'm not recalling (it was in 2007) ... say 2 or 3 hours) or unscrew a bleeder on one of the calipers to release the pressure.

Then, after a random time, the situation recurring.
Bad master cylinder. Its the only thing that creates or holds pressure in the braking system. Get an OEM unit if you can.
 

Mtntopper

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Bad master cylinder. Its the only thing that creates or holds pressure in the braking system. Get an OEM unit if you can.
When you release the built-up pressure at one of wheels, you should hear a faint ticking or click at the master cylinder as it resets. If you hear that, the master is bad. I went through 2 rebuilt master cylinders with the same issue. After installing a new, not rebuilt, OEM unit, I've been free to move on to the next issue...
 

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