Went for a little drive. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**bigdon-70blazer** · 07-17-2010, 11:34 PM

Took the Blazer for a little drive this eve. The brakes are HORRIBLE ! I changed everything when I restored her. I rebuilt all the wheel cylinders and the master cylinder myself. Bled the brakes but at regular driving, it was like not having brakes. Any suggestions? Should I start at the master cylinder, replace it with a rebuilt one then the wheel cylinders? I changed all the brake lines also with stainless stuff from inline tube. I think I got my throttle thing worked out, actually got it up to 55 miles per hour, still got some shakedown to do.

bouncytruck · 07-17-2010, 11:36 PM

I'd start by bleeding the system to make sure it doesn't have any air in the lines.

**bigdon-70blazer** · 07-18-2010, 08:35 AM

Will do!

Long Roof · 07-18-2010, 10:08 AM

I would also bleed the system again. After that I would look at the MC. If its a rebuilt one I would be suspicious. I went through two bad rebuilt MC's on a vette once before using a brand new one which worked fine. Good luck.

BLUE THUNDER · 07-18-2010, 12:56 PM

Brake booster? It could be leaking vacuum.

Critter · 07-18-2010, 02:45 PM

I also would look at the master cylinder.

If you had one bad wheel cylinder or caliper it would probably be leaking or you would notice one corner of the vehicle not braking properly. Sounds like all 4 corners of yours are equally not working. So after one more good bleeding just to be sure, I would look at the MC. The booster wouldn't cause this problem, it would just cause you to lose the "power" feel, not the braking itself.

*72lb4x4* · 07-18-2010, 03:50 PM

How does the pedal feel when you step on the brake?
Step on the brake and then start the engine. The pedal should sink a bit when the booster gets vacuum.
Does the emergency brake work right?

Jtrux · 07-18-2010, 04:32 PM

Does it have drums on all 4 corners?

**bigdon-70blazer** · 07-18-2010, 05:18 PM

No power for me! It has 4 corner drums. And I rebuilt the master cylinder myself, a job I had never done but it was not that complicated so that could be the problem also. The brakes feel hard enough just not enough braking for the amount of force I seem to be giving. Boy, rebuilding a car is fun!

low'n slow · 07-18-2010, 07:48 PM

Did you "bench bleed" the master cylinder?

Critter · 07-18-2010, 10:28 PM

Quote:

Originally Posted by bigdon-70blazer

No power for me! It has 4 corner drums. And I rebuilt the master cylinder myself, a job I had never done but it was not that complicated so that could be the problem also. The brakes feel hard enough just not enough braking for the amount of force I seem to be giving. Boy, rebuilding a car is fun!

Well there's your problem! You need power disk brakes!

I'm kidding but not really. I can't remember, did you drive this blazer before the rebuild? Are you familiar with how non-power drums are supposed to feel??? I'm sure you are.

On my 68 truck with the same setup I had to spend hours adjusting the so called "self adjusters" because they weren't doing their job! Have you tried backing them out a little?

72Levi · 07-18-2010, 11:23 PM

You need to adjust the brakes more. Turn the drums by hand and completely tighten them with the adjusters, then back them off until you can actually hear the shoes with the drums. If your MC is ok, the problem is adjustment.

Critter · 07-19-2010, 12:03 AM

Quote:

Originally Posted by 72Levi

You need to adjust the brakes more. Turn the drums by hand and completely tighten them with the adjusters, then back them off until you can actually hear the shoes with the drums. If your MC is ok, the problem is adjustment.

That's what I was getting at, I'm just a little "longer winded".

**bigdon-70blazer** · 07-19-2010, 08:38 AM

I will try this...Thanks!

cleszkie · 07-19-2010, 02:08 PM

x2 on the bench bleeding of the master cylinder. I also highly recommend getting some of those "one man" brake bleeder screws for each of your brake pistons. These prevent backflow of fluid and air into the pistons as you pump the pedal. You don't need a second person to open and close the screw. Can get them in any parts store in the "Help" section for a few bucks.

07-17-2010, 11:34 PM	#1
bigdon-70blazer Registered User Join Date: Jan 2007 Location: Poplar Bluff, MO Posts: 1,501	Went for a little drive. Took the Blazer for a little drive this eve. The brakes are HORRIBLE ! I changed everything when I restored her. I rebuilt all the wheel cylinders and the master cylinder myself. Bled the brakes but at regular driving, it was like not having brakes. Any suggestions? Should I start at the master cylinder, replace it with a rebuilt one then the wheel cylinders? I changed all the brake lines also with stainless stuff from inline tube. I think I got my throttle thing worked out, actually got it up to 55 miles per hour, still got some shakedown to do.

07-17-2010, 11:36 PM	#2
bouncytruck SKINNY TIRES RULE! Join Date: Sep 2001 Location: Bothell, WA Posts: 11,049	Re: Went for a little drive. I'd start by bleeding the system to make sure it doesn't have any air in the lines. __________________ bouncytruck 1972 K5 The Hauler 1994 K1500 Suburban The Daily2010 Kia Soul Wife's Ride2014 Fiat 500L

07-18-2010, 08:35 AM	#3
bigdon-70blazer Registered User Join Date: Jan 2007 Location: Poplar Bluff, MO Posts: 1,501	Re: Went for a little drive. Will do!

07-18-2010, 10:08 AM	#4
Long Roof Old School, New Style Join Date: Jun 2005 Location: Monroeville, Ohio Posts: 790	Re: Went for a little drive. I would also bleed the system again. After that I would look at the MC. If its a rebuilt one I would be suspicious. I went through two bad rebuilt MC's on a vette once before using a brand new one which worked fine. Good luck. __________________ The Good: - 72 GMC Jimmy 4x4 - 307 cid / 350 th - 70 Chevy Suburban 1/2T 2wd - 454 cid /400 th - 96 Chevy Impala SS - mainly stock - 98 Chevy Tahoe LT 4x4 - all stock The Bad: - 86 Chevy Suburban 1/2T 4x4 - winter beater The Ugly: - 72 Chevy Suburban 1/2T 2wd - parts truck

07-18-2010, 12:56 PM	#5
BLUE THUNDER Registered User Join Date: May 2007 Location: San Antonio Posts: 993	Re: Went for a little drive. Brake booster? It could be leaking vacuum.

07-18-2010, 02:45 PM	#6
Critter Future TOTM Winner Join Date: Aug 2006 Location: Bulverde, TX Posts: 2,692	Re: Went for a little drive. I also would look at the master cylinder. If you had one bad wheel cylinder or caliper it would probably be leaking or you would notice one corner of the vehicle not braking properly. Sounds like all 4 corners of yours are equally not working. So after one more good bleeding just to be sure, I would look at the MC. The booster wouldn't cause this problem, it would just cause you to lose the "power" feel, not the braking itself. __________________ 72 Chevy CST K5 HIGHLANDER BLAZER Getting a 6.0,NV4500,NP205,14BFF (Currently laying all over the place in little pieces) 72 Chevy swb step-side "LS" 6.0 Here's a build thread of sorts 2002 HD2500 Crew Cab, 8.1L Allison 4x4 Daily Driver Check it out www.lsdyno.com

07-18-2010, 03:50 PM	#7
72lb4x4 Account Suspended Join Date: Jul 2006 Location: DFW Posts: 1,427	Re: Went for a little drive. How does the pedal feel when you step on the brake? Step on the brake and then start the engine. The pedal should sink a bit when the booster gets vacuum. Does the emergency brake work right?

07-18-2010, 04:32 PM	#8
Jtrux I'm a poor spectator Join Date: Aug 2006 Location: San Antonio, Tx Posts: 2,287	Re: Went for a little drive. Does it have drums on all 4 corners? __________________ 2006 Jeep Unlimited IMPACT ORANGE 1993 Chevy 2500 4x4 ExCab LWB 454/NV4500 Tow rig 1977 Ford F100 2x4 LWB 1st truck I owned, still have it!!! 1979 Ford F150 4x4 SWB Built Ford Tough!!! 1971 Chevy Blazer 350 / SM465 / NP205 UNDER CONSTRUCTION Soon to have a LQ4 6.0!!!

07-18-2010, 05:18 PM	#9
bigdon-70blazer Registered User Join Date: Jan 2007 Location: Poplar Bluff, MO Posts: 1,501	Re: Went for a little drive. No power for me! It has 4 corner drums. And I rebuilt the master cylinder myself, a job I had never done but it was not that complicated so that could be the problem also. The brakes feel hard enough just not enough braking for the amount of force I seem to be giving. Boy, rebuilding a car is fun!

07-18-2010, 07:48 PM	#10
low'n slow Too Dumb To Know Better Join Date: Nov 2005 Location: Texas Posts: 882	Re: Went for a little drive. Did you "bench bleed" the master cylinder? Last edited by low'n slow; 07-18-2010 at 07:49 PM.

07-18-2010, 11:23 PM	#12
72Levi Active Member Join Date: Feb 2006 Location: sa tx Posts: 851	Re: Went for a little drive. You need to adjust the brakes more. Turn the drums by hand and completely tighten them with the adjusters, then back them off until you can actually hear the shoes with the drums. If your MC is ok, the problem is adjustment. __________________ 1972 K5 Blazer ALL ORIGINAL paint & engine, A/C, Tilt, 4sp, AM/FM, Tow Hooks, Aux Battery Tray, Tach, Vacuum 2004 FORD FX4 SuperCrew 2005 CTS-V 12 sec family car 2008 Buick Enclave AWD, Nav, & DVD, Wife LOVES it!

07-19-2010, 08:38 AM	#14
bigdon-70blazer Registered User Join Date: Jan 2007 Location: Poplar Bluff, MO Posts: 1,501	Re: Went for a little drive. I will try this...Thanks!

07-19-2010, 02:08 PM	#15
cleszkie Registered User Join Date: Feb 2003 Location: Santa Ana, CA Posts: 2,191	Re: Went for a little drive. x2 on the bench bleeding of the master cylinder. I also highly recommend getting some of those "one man" brake bleeder screws for each of your brake pistons. These prevent backflow of fluid and air into the pistons as you pump the pedal. You don't need a second person to open and close the screw. Can get them in any parts store in the "Help" section for a few bucks.



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