new surge brakes very hot

scott free

Recruit
Joined
Aug 11, 2009
Messages
2
Installed new master cylinder, brakes and rotors. When arrived home wheels very hot, pads smelling burned. Dual axle trailer, brakes on one axle. Backing up is not a problem. Anyone have any ideas, so far out big bucks for hot wheels! thanks
 

45Auto

Commander
Joined
May 31, 2002
Messages
2,842
Re: new surge brakes very hot

Did you adjust the brakes?

Jack each wheel up and make sure it spins freely without dragging. If it's dragging, then back the brakes off. If they're not dragging, they won't get hot.
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
15,414
Re: new surge brakes very hot

Rotors? Disc?
Did you replace the master cylinder with a disc compatible unit? There is a difference between drum an disc master cylinders.
 

Pez Vela

Chief Petty Officer
Joined
Dec 4, 2004
Messages
504
Re: new surge brakes very hot

Could be any one of a number of things. Over tight nut on axle bearings or dragging brake calipers come to mind. Relieve any pressure on the master (surge actuator), jack up the hot ones, try to spin the tires by hand, and see if the brake calipers (pads) are dragging on the rotors. That's a start. If this was a shop, I'd be on the phone, because something's very wrong for this to happen with new parts (but relatively common with old rusty wheel cylinders).
 

egclassic

Petty Officer 2nd Class
Joined
Dec 13, 2009
Messages
128
Re: new surge brakes very hot

I have this same problem but only on one side. Traced it to a sticking master cylinder. I know, yours are new but weirder things have happened. Like others have said, check the adjuster.
 

gozierdt

Petty Officer 1st Class
Joined
Jun 13, 2010
Messages
364
Re: new surge brakes very hot

I'd double check the master cylinder you put on. Drum brake master cylinders have a residual pressure valve that doesn't allow all the fluid to flow back into the master cylinder, keeping the brake pads out near the drums. Disk brake's don't need that residual pressure, and if the system has this valve in it, the pads can't back away from the disks the couple of thousands of an inch they need to to let the disk turn freely. The valve is typically a small check valve inside the exit port from the master cylinder. You could do a partial check by jacking one wheel, and applying brake pressure by pushing on the coupler- probably did that while bleeding the system. If the jacked-up wheel won't turn freely after releasing the brake pressure, you've got the wrong master cylinder.
 

45Auto

Commander
Joined
May 31, 2002
Messages
2,842
Re: new surge brakes very hot

Whoops, didn't notice he said rotors. Gonna have a hard time adjusting those disk brake calipers.......... :eek:
 

dockwrecker

Lieutenant
Joined
Mar 10, 2006
Messages
1,392
Re: new surge brakes very hot

I'd double check the master cylinder you put on. Drum brake master cylinders have a residual pressure valve that doesn't allow all the fluid to flow back into the master cylinder, keeping the brake pads out near the drums. Disk brake's don't need that residual pressure, and if the system has this valve in it, the pads can't back away from the disks the couple of thousands of an inch they need to to let the disk turn freely. The valve is typically a small check valve inside the exit port from the master cylinder. You could do a partial check by jacking one wheel, and applying brake pressure by pushing on the coupler- probably did that while bleeding the system. If the jacked-up wheel won't turn freely after releasing the brake pressure, you've got the wrong master cylinder.

You nailed it. The master cylinders are slightly different for disc brakes.
You can fix your master however. There's a plastic washer at the end of the piston assy that should have a 1/16" dia hole drilled in it to eliminate the residual pressure. Take the cylinder apart and drill the hole. Problem solved.
 

mikeneal

Senior Chief Petty Officer
Joined
Jan 28, 2004
Messages
710
Re: new surge brakes very hot

Yup, I bet wrong master cylinder, post model number and easy to tell.
 
Top