Author Topic: 69 RF brake lock up?  (Read 8969 times)

jvb6648

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Re: 69 RF brake lock up?
« Reply #105 on: December 23, 2016, 09:07:27 PM »
Jim, Do you have access to a couple of scales, maybe a highway patrol or trooper friend who works truck inspections. You mentioned that this was a drag car for a while. If the body is twisted it could make the R/F light and make less work for that brake causing the lock up.
Jim
Jim
68 Z/28

Rufcar

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Re: 69 RF brake lock up?
« Reply #106 on: December 23, 2016, 11:24:01 PM »
With just about everything replaced Im taking time to re
think what my next step is. I will let everyone know how I make out in the up coming weeks. Happy holidays to all!

Dave Siltman

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Re: 69 RF brake lock up?
« Reply #107 on: December 27, 2016, 01:14:17 AM »
Did you ever measure the wheelbase from side to side? Back in the '80s we "staggered" the front wheels in my Chevelle drag car to get about an inch and a half more rollout in the starting beams. If you slammed the brakes and weren't ready for it, the car would dart to the right because that front wheel was set back farther than the left. I'd try measuring the centerline from side to side and then get the car in the air and get it "squared". If for nothing else, it might eliminate something else from the equation.

Rufcar

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Re: 69 RF brake lock up?
« Reply #108 on: December 27, 2016, 08:24:33 PM »
Dave I didn't actually measure the front but I have set up on a 4 wheel alignment machine. It was a dag car years ago but I figured the 4 wheel adj would catch that? 
After I wrote that paragraph I took the old girl out for a drive and after my last plumbing which was to put the left wheel into the larger hole of the distribution block on fender side and the RF to the engine side and smaller hole and the MC to the front center hole the car was much better. I drove on back roads and braked a lot and as long as I didn't HIT the brakes but only pushed on them the car was fine. Though even at slow speeds, like approaching a light if I pushed a bit harder it would lock up and release. The way it is now seems to work better then it ever did though not perfect. Since it is a 4 speed with huge torque and compression the car always slowed easily. I can def live with it like this or until I find the answer. Tkx Guys! Jim
« Last Edit: December 27, 2016, 09:44:35 PM by Rufcar »

1969Z27

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Re: 69 RF brake lock up?
« Reply #109 on: January 29, 2017, 05:19:50 PM »
Hi Jim. Have you made any progress? I was having similar problem with my 1997 GMC truck and thought I'd share how I fixed it.
One rear wheel cylinder was leaking. So I replaced both. Brakes worked fine until the humidity got really high or during rainy spells.
That's when barely touching the pedal right rear would lock up. After the humidity and storms passed it would go back to working fine.
I thought it might have something to do with the brake fluid that had been absorbed into the brake shoe. I switched the shoes from one side
to other side. Sure enough during the next rain the left rear would lock up barely touching the pedal. Replaced both sides with new shoes.
Haven't had any issues since.
Russ 
68 RS L22/M20
69 SS L48/MC1

Rufcar

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Re: 69 RF brake lock up?
« Reply #110 on: February 04, 2017, 03:37:46 PM »
69z27, I did have a rear leak in new cylinders and changed that one re adjusted both right front still locks up. I sort of gave up as I changed everything and it made no difference.  I have been driving it that way now for close to 5k mi. I know how to stop without locking by just slowing down gently. 

myblue67

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Re: 69 RF brake lock up?
« Reply #111 on: July 12, 2017, 12:24:41 AM »
Did you reach any conclusions? Similar problem. A new master cylinder fixed the problem for about three months...now returned. Hard to believe it is a MC again.

Rufcar

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Re: 69 RF brake lock up?
« Reply #112 on: November 01, 2017, 06:24:22 PM »
Sorry I have not been on all summer. I was completing my 70 Chevelle full restoration, also did a 71 Rolls coupe and just now finished a 89 Jeep YJ. I drove the Camaro approx. 1000 mi this summer with the brake problem. I have replaced and tested every brake component and in the end nothing helped! RF still locks up under light pressure. I even gave the car to another 40 yr experienced mechanic who swapped and tested everything and accomplished nothing. Spoke to several experienced muscle car specialist around the US and to date its still exactly the same. So for now It will stay like it is as I can drive around it and have for 4 years now. Over the winter I may go it once again. Tkx Jim F