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

Hightower79 · 08-20-2019, 03:00 PM

67 with Drum brakes all around (no servo).

After a long time off the road I took my truck for test drive. I was happy with all the work I had done, however I have a brake problem.

When lightly applying the brakes the truck pulls to the right and there is little brake effort (certainly less than expected). If I keep applying foot pressure to the brakes (Braking harder) there is little more brake effort until the LH wheel locks up.

Before I strip things apart am I likely looking at a RH or a LH brake issue?

Also, can someone tell me if the rear (firewall) master cylinder bowl goes to the fronts, as this was a lower level than expected.

OregonNed · 08-20-2019, 03:16 PM

On my '68 with a little pull, it took some time, but once I had both fronts adjusted I was good to go.. may or may not be the issue, It was a pain testing, jacking up to adjust, trying again...etc.

**Steeveedee** · 08-20-2019, 03:19 PM

You probably have a leaking wheel cylinder on the side that grabs with little pedal pressure and then won't lock up on hard braking. I THINK that the front reservoir is for the front brakes. Trace the lines, that will tell you.

**FirstOwner69** · 08-20-2019, 03:36 PM

^^^^ What he said. I've experienced the same thing a couple times. Both times (most recently when I completed my resto) the pull was caused by a leaking wheel cylinder on the side that was pulling. If you ride the brakes lightly for a block or 2 does it go away?

Hightower79 · 08-20-2019, 08:24 PM

Quote:

Originally Posted by Steeveedee

You probably have a leaking wheel cylinder on the side that grabs with little pedal pressure and then won't lock up on hard braking. I THINK that the front reservoir is for the front brakes. Trace the lines, that will tell you.

The left wheel locks up with hard braking. I'm getting very little braking straight to a lock-up.

I will trace the lines in the morning and will remove the front left drum at the same time.

Might be time for discs and a power brake set-up.

**Wrenchbender Ret** · 08-20-2019, 10:32 PM

I agree it probably is fluid or grease leaking on the linings. I have had problems with the linings they use on drum brakes anymore. Seems like they don't care about drum brakes. Its a good idea to grind or file or sand a bevel on the edge of the linings. This keeps them from digging in & pulling or grabing.
George

Hightower79 · 08-21-2019, 09:05 PM

Both front brakes/hubs checked. No sign of fluid contamination or grease. Both slave cylinders appear to be working smoothly. Points of note were that the RH brake shoes were out of adjustment by quite a bit. The adjusting screw was seized. It's now working and adjusted as it should. Other points were that the outer bearings are badly pitted on both sides and I washed lots of metel filings out. New bearings on order.

I will check the rear shoes tomorrow.

08-20-2019, 03:00 PM	#1
Hightower79 Registered User Join Date: Sep 2017 Location: Portmouth UK Posts: 9	Brake problem. 67 with Drum brakes all around (no servo). After a long time off the road I took my truck for test drive. I was happy with all the work I had done, however I have a brake problem. When lightly applying the brakes the truck pulls to the right and there is little brake effort (certainly less than expected). If I keep applying foot pressure to the brakes (Braking harder) there is little more brake effort until the LH wheel locks up. Before I strip things apart am I likely looking at a RH or a LH brake issue? Also, can someone tell me if the rear (firewall) master cylinder bowl goes to the fronts, as this was a lower level than expected.

08-20-2019, 03:16 PM	#2
OregonNed Registered User Join Date: Dec 2012 Location: Vancouver, Washington Posts: 1,644	Re: Brake problem. On my '68 with a little pull, it took some time, but once I had both fronts adjusted I was good to go.. may or may not be the issue, It was a pain testing, jacking up to adjust, trying again...etc. __________________ 1968 Chevrolet C/10 LWB - 327, TH350 - 4/5 Drop

08-20-2019, 03:19 PM	#3
Steeveedee Who Changed This? Join Date: Jan 2013 Location: Simi Valley, CA Posts: 10,102	Re: Brake problem. You probably have a leaking wheel cylinder on the side that grabs with little pedal pressure and then won't lock up on hard braking. I THINK that the front reservoir is for the front brakes. Trace the lines, that will tell you. __________________ ~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA

08-20-2019, 03:36 PM	#4
FirstOwner69 Senior Member Join Date: May 2010 Location: Wisconsin & Arizona Posts: 4,839	Re: Brake problem. ^^^^ What he said. I've experienced the same thing a couple times. Both times (most recently when I completed my resto) the pull was caused by a leaking wheel cylinder on the side that was pulling. If you ride the brakes lightly for a block or 2 does it go away?

08-20-2019, 10:32 PM	#6
Wrenchbender Ret Registered User Join Date: Oct 2005 Location: Overland Park, Ks. Posts: 5,190	Re: Brake problem. I agree it probably is fluid or grease leaking on the linings. I have had problems with the linings they use on drum brakes anymore. Seems like they don't care about drum brakes. Its a good idea to grind or file or sand a bevel on the edge of the linings. This keeps them from digging in & pulling or grabing. George Last edited by Wrenchbender Ret; 08-21-2019 at 10:19 PM.

08-21-2019, 09:05 PM	#7
Hightower79 Registered User Join Date: Sep 2017 Location: Portmouth UK Posts: 9	Re: Brake problem. Both front brakes/hubs checked. No sign of fluid contamination or grease. Both slave cylinders appear to be working smoothly. Points of note were that the RH brake shoes were out of adjustment by quite a bit. The adjusting screw was seized. It's now working and adjusted as it should. Other points were that the outer bearings are badly pitted on both sides and I washed lots of metel filings out. New bearings on order. I will check the rear shoes tomorrow.



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