Rear Brakes Lock Up M1028

[rsrxc700]

Rear Brakes lock up on me driving in the rain, sketchy.... Have not had it happen in the dry.

Does this have something to do with the ride height proportioning valve and/or its adjustment.?

Communication shelter has been removed and will be driving this empty 99% of the time .

Should I disable it?

Thanks!

 

[cucvrus]

I would look at what is causing the lock up. Have you ever had the drums removed and looked at the condition of the axle seals and wheel cylinders? That is where I would start. Most time brakes lock up because of an issue with oil or improper adjustment. Could be proportioning valve issues. Check it out carefully and find the issue before you start adding to the issue. I have had that rear axle proportioning valve operational on all my pick-ups. I know GM had a bulletin for removing them. Good Luck. Oil-soaked brake lining is affected by rain and damp weather.

 

[nyoffroad]

I know it doesn't sound 'right' but oil or brake fluid does cause brakes to lock up NOT slip, I've had that argument several times. If both wheels seem to be locking the same then I would try disconnecting the ride valve and try it set at different heights, IIRC you want it tied up to simulate an empty bed.

 

[87cr250r]

I know it doesn't sound 'right' but oil or brake fluid does cause brakes to lock up NOT slip, I've had that argument several times. If both wheels seem to be locking the same then I would try disconnecting the ride valve and try it set at different heights, IIRC you want it tied up to simulate an empty bed.

I second this comment. Every time I've had leaky axle seals or wheel cylinders I've had grabby brakes. In fact, my M1008 has a leaking hub seal and the shoes are nearly worn out on that side while the other side is nearly new.