Brake Question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

68-BEAST · 04-11-2006, 02:57 AM

Hello, I am new to this site and I am having a terrible time with my brakes. I own a 68 GMC Suburban, 3/4 ton, 4x4, rust magnet. It has been a project for the last 5 years, the brakes have never worked right. They finally went out all together and so I just replaced all the shoes front and back. The wheel cylinders seem like they are in good working order but I can only get 1 of 4 to bleed correctly. The front right bleeds just fine, but I can't get good pressure from the others. I unscrewed the lines fromt the bottom of the porportioning valve under the master cylinder, and I get good pressure there, it spurts brake fluid when pedal applied.

While checking the wheel cylinders, the whole system was pretty much dry. I have worked for a few hours and can't get any pressure, brake pedal just goes to the floor. I have manually adjusted the shoes to be touching the drums. I am not a great mechanic by any means, but I've bled brakes before and never had this much of a problem. Where should I look first????

68-BEAST

krue · 04-12-2006, 03:13 AM

What shape are the flex lines in? Try disconnecting them from the wheel cylinders and see if you're getting fluid thru them.

qksilver · 04-12-2006, 11:54 PM

sometimes when bleeding an old M/S it will stick.
What happens is that it wears under normal use but when you bleed the plunger gets pushed past the normal wear and sticks.
When bleeding a used M/S slowly pump but never push it to the floor

68-BEAST · 04-23-2006, 03:29 AM

ok thanks guys, I will let you know how it turns out

68-BEAST

04-11-2006, 02:57 AM	#1
68-BEAST Registered User Join Date: Apr 2006 Location: Mount Vernon, WA Posts: 7	Brake Question Hello, I am new to this site and I am having a terrible time with my brakes. I own a 68 GMC Suburban, 3/4 ton, 4x4, rust magnet. It has been a project for the last 5 years, the brakes have never worked right. They finally went out all together and so I just replaced all the shoes front and back. The wheel cylinders seem like they are in good working order but I can only get 1 of 4 to bleed correctly. The front right bleeds just fine, but I can't get good pressure from the others. I unscrewed the lines fromt the bottom of the porportioning valve under the master cylinder, and I get good pressure there, it spurts brake fluid when pedal applied. While checking the wheel cylinders, the whole system was pretty much dry. I have worked for a few hours and can't get any pressure, brake pedal just goes to the floor. I have manually adjusted the shoes to be touching the drums. I am not a great mechanic by any means, but I've bled brakes before and never had this much of a problem. Where should I look first???? 68-BEAST

04-12-2006, 03:13 AM	#2
krue Designated A-hole! Join Date: Mar 2003 Location: South Mississippi Posts: 36,450	Re: Brake Question What shape are the flex lines in? Try disconnecting them from the wheel cylinders and see if you're getting fluid thru them. __________________ "If it ain't broke, fix it 'til it is!" Being stupid ain't illegal. We're Still Debt Free Except for the House!!! www.daveramsey.com 70 GMC SWB Stepside project "Green Booger" soon to be 6.0l/4l80e 93 S-10 "Poppaw's Truck"

04-12-2006, 11:54 PM	#3
qksilver Senior Member Join Date: Dec 2004 Location: Southern Pines NC Posts: 3,853	Re: Brake Question sometimes when bleeding an old M/S it will stick. What happens is that it wears under normal use but when you bleed the plunger gets pushed past the normal wear and sticks. When bleeding a used M/S slowly pump but never push it to the floor

04-23-2006, 03:29 AM	#4
68-BEAST Registered User Join Date: Apr 2006 Location: Mount Vernon, WA Posts: 7	Re: Brake Question ok thanks guys, I will let you know how it turns out 68-BEAST



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