Front Brake Calipers Hang Up (Binding)

[Arberg0]

From: papamgb1 (Original Message) Sent: 11/25/2004 10:24 AM

hello ya all and I hope some one can help....I have replaced bothe front calipers and the master cylinder and the front pads continue to hang up why oh why is this happening??

 

From: denison Sent: 11/25/2004 11:52 AM
I can think of a couple of reasons, though yours is so much newer than any brakes I have experience with, there might be more causes I dont know about.
Anyway my guesses: The piston in your master cylinder must be able to return fully to its -rest- position, or the compensating ports between the reservoir and the master cylinder wont be opening. These ports allow the brake fluid to expand back into the reservoir when it heats up - such as the hot calipers would cause. If the actuator rod that pushes the piston into the master cylinder is just a millimeter too long, this could happen. It could keep the pads from releasing, and the further you drove it, the hotter the rotor/pads/calipers would be getting, and the worse it would be. It should be okay after sitting for a few hours though - until the next time you had to use the brakes enough for them to get warm!
There might be clogged residual pressure valves on your master cylinder, or on the item where the two halves of your brake system both join - on a Chevy chassis it might be called the brake Combination Valve. This Combination Valve is the goody that senses when one side of your brake system is losing fluid and makes the Brake Indicator on the dashboard light up. It is possible that crud got into these valves when you bled the system after repacing the parts. These valves might also be on the master cylinder instead. They might be invisible from the outside too.
With an RV only 11 years old it would be very unlikely to have a deteriorated brake hose - but I suppose it could happen. Old brake hoses can swell on the inside, closing off the backflow of fluid when you take your foot off the brakes.
If your RV has the hydroboost brake system, where the power steering fluid also supplies the boosting force for the power brakes, then it might be time to get the hydroboost rebuilt - in case it isnt fully releasing the master cylinder piston.
If you had the rotors off when you replaced the front calipers, then make sure the rotors are running true, and didnt get bolted back on with something jammed between them and the hub, causing excessive runout.
If your RV has ABS brakes, a pressure proportioning valve for the rear brakes, or a tag axle with a separate brake booster - I know nothing about them. 



From: papamgb1 Sent: 11/25/2004 12:42 PM
denison, you are a very knowledgable thank you so much  Papa Smurf

   

From: Gizmostail1 Sent: 12/5/2004 10:27 PM
I have a theory that might help as well..  If you have replaced the master cylinder and brakes .. etc.. you might look at the break lines.. when you hit your breaks you need to let the fluid back to the mastercylinder to release them .. If the break lines are clogged the pressure to make the breaks work is very stong and they will grab fine.. BUT..  the pressure to return the fluid is then plugged and it takes a while to release the pads..  Just a thought..