Brake problem
 

The front discs on my '72 squeak to the point of embarrassment. A quick check thru the rims revealed there's plenty of pad left, and the rotors look ok. I figured I'd begin with the easy stuff first and bleed the brakes. The forward reservoir in the master cylinder was way low (tracing the line, it leads to the rear brakes... got a leak there somewhere). Reading up on the subject, I learned that the combination valve must be held open during the bleeding process by holding in the metering pin. I'm not sure where this pin is. If it is on the forward end of the combo valve body, mine appears to be stuck in the "in" position. The end of the pin is flush with the boss thru which it protrudes. I'm new to this type of brake system, incorporating a combo valve. What's my next step?

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72 Chevy K20 LWB, 350/350, lifted, dual shock suspension F&R.
AKA The Beast. Daily driver, even though it's a work in progress.

maybe the front brakes have gotten hot due to them being your stopping power. The pads themselves may be glazed. I would suggest fixing the rear leak and then replacing the front pads.

I am no pro, just my opinion.

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1971 Chevy 1/2t, 350
1998 Yamaha V-Star 650
1970 Chevy 3/4t, I6(freshly rebuilt), 4 speed
Keokuk,IA

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MSN Messenger = boilrman
Find a job you love and you'll never have to work a day in your life.



[This message has been edited by boilrman (edited March 20, 2002).]

Right you are. Both rear wheel cylinders are leaking. And I've got come rust contamination in the system. Got a big job ahead of me.

Can you address the combo valve issue?

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72 Chevy K20 LWB, 350/350, lifted, dual shock suspension F&R.
AKA The Beast. Daily driver, even though it's a work in progress.

think i remember seeing in another post about the valve issue. He was unable to bleed the rear brakes until he bled the front and then the valve you are talking about moved and he was able to bleed the rear.

If your rear pads are soaked with brake fluid, I am sure they are if the wheel cylinders have been leaking for a while, replace them. They can get sticky.

Good Luck.

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1971 Chevy 1/2t, 350
1998 Yamaha V-Star 650
1970 Chevy 3/4t, I6(freshly rebuilt), 4 speed
Keokuk,IA

http://communities.msn.com/SchweringFamily/shoebox.msnw

MSN Messenger = boilrman
Find a job you love and you'll never have to work a day in your life.

it could actually be the axleshaft seals leaking, greas eon shoes wil make linings grab the drums and lock em up when truck is unloaded, leaking seals is very common problem on the eaton 3/4 and 1 ton axles in 67-72

sqealing pads is caused by two things, either the pads are metallica composition and youl have to live with it unless you replace them, or they pads are loose in the calipers and need anti sqeal applied to the backsides of them, you can get the stuff at auto parts store

good luck

The pin on the combination valve sit flush with the boss when brakes are not applied. Have someone press the brakes and you should see it stick out. That's when you want to push it back in and hold it there while bleeding the rear brakes. That's when 2 assistants are useful unless you have a special tool to hold it in. You don't need to do anything with it during front brake bleeding process.

Ok, now it makes sense. I was fooling with this solo, and since my only other Chevy was a '65 El Camino, I'd never taken notice of a combo valve before... so I didn't know what to look for. Thanks Alex.

Fast68Chevy, I'm sure it's the rear wheel cylinders. While I was fooling with it yesterday, I pumped the brakes a bunch and was rewarded with 2 puddles of brake fluid on the street. That, in addition to the problem with the calipers up front and system contamination, the Beast is on the bench until I can rip into it.

boilrman, I'll look for that other post.

Thanks to you all for your advise. Glad I discovered this BBS. There's a wealth of good info here.

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72 Chevy K20 LWB, 350/350, lifted, dual shock suspension F&R.
AKA The Beast. Daily driver, even though it's a work in progress.