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

Tachout · 10-08-2013, 01:24 PM

Today I drove my C20 to work for the first time. It is the factory Drum Brakes. It has been a while since I drove a vehicle with drum brakes. They leave a lot to be desired. Everything worked fine till I hit the offramp. The brake pedal got soft on me. I was on them pretty hard, but the pedal was soft and fading to the floor. I down shifted, and slowed down, and when I got around the off ramp corner, and down the hill I slowed down. Got pulled to a curb and as I stepped on the brakes they were normal again. Finished the 4 blocks and 2 turns to work and again the pedal was normal. Got out of the truck, came in to work, and got all set up. Went back down and checked the fluid. Fill and clear. I then checked the pedal and it feels normal. Could this have just been because they were hot, or is it time for a master cylinder? I do want to replace the brake hoses, and the battery and battery box this payday. If this needs a new master I will throw that on as well.

This is a 1967 C30 with SBC and Manual Brakes.

**Stocker** · 10-08-2013, 02:47 PM

Start by bleeding the brakes. If there's air in the lines and you get a soft pedal, you can often get a harder pedal by 'pumping' the brakes..... that is, pressing the pedal more than once. Kinda sounds like that's what happened to you, soft pedal then when you pressed it again it was better.

Reading your post I didn't notice anything that would have caused the brakes to overheat, which of course would have caused decreased stopping power but the pedal should have still been hard if overheating was the problem.

If bleeding doesn't fix it, try replacing the master cylinder. Fluid could be full, no air in system, but fluid bypassing internally. It's not uncommon.

Tachout · 10-08-2013, 02:51 PM

Thanks, it does not feel like air in the lines, and this was the only time I felt that soft pedal. I think to be on the safe side I have talked myself into a full front brake job, including a new master cylinder this weekend. Might just do te rears at the same time.

Lou Boffa · 10-08-2013, 04:43 PM

I got unassisted drums too. Even though I can lock the wheels with enough (a lot of) pressure, still scare the $#!^ out of me periodically. I got to get a booster added. That should help.

*Fitz* · 10-08-2013, 05:29 PM

Quote:

Originally Posted by Tachout

Thanks, it does not feel like air in the lines, and this was the only time I felt that soft pedal. I think to be on the safe side I have talked myself into a full front brake job, including a new master cylinder this weekend. Might just do te rears at the same time.

Why replace a perfectly good master cylinder when a trip to your nearest parts store will get you a rebuild kit for it for about 10 bucks? And It's Soooo Hard to rebuild one....takes all of, oh, 5 minutes.

*Mister-B* · 10-08-2013, 06:05 PM

Quote:

Originally Posted by Fitz

Why replace a perfectly good master cylinder when a trip to your nearest parts store will get you a rebuild kit for it for about 10 bucks? And It's Soooo Hard to rebuild one....takes all of, oh, 5 minutes.

A new master cylinder is only $17 from oreilly , and if he goes the power brake booster route, he can order one with the MC included, which usually ends up being an even better deal. Your option is good too, but if he's never rebuilt one, it's one more thing to fuss with, and not much payoff.

OP, you should seriously consider a brake booster. It will make all the difference. I would suspect you have one or more cylinders that are leaking too.

*Fitz* · 10-08-2013, 06:10 PM

Quote:

Originally Posted by Mister-B

A new master cylinder is only $17 from oreilly , and if he goes the power brake booster route, he can order one with the MC included, which usually ends up being an even better deal. Your option is good too, but if he's never rebuilt one, it's one more thing to fuss with, and not much payoff.

OP, you should seriously consider a brake booster. It will make all the difference. I would suspect you have one or more cylinders that are leaking too.

But what is life if you don't learn at least one new thing every day?

In The Ten Ring · 10-08-2013, 06:56 PM

Quote:

Originally Posted by Fitz

But what is life if you don't learn at least one new thing every day?

A lot less stressful and cheaper.

*Mister-B* · 10-08-2013, 07:02 PM

Quote:

Originally Posted by Fitz

But what is life if you don't learn at least one new thing every day?

Well, lol...it's sometimes less stressful, but I get where you're coming from.

He's got a couple good options

Tachout · 10-09-2013, 10:43 AM

I looked at it last night and both front brake hoses are leaking. I suspect that is the root of the problem. The fluid looks rusty, and that is also not a good sign.

I had considered that I could rebuild the one I have, along with rebuilding the wheel cylinders that I am sure could use a freshening, but to be honest the time it would take to get the kits, do the rebuild on the master (That I have done before seveal times) it is much less of a hassel to just bolt on the new parts, bleed everything and be done with it. Having all the rubber components replaced on something this old when it comes to stopping would give me peace of mind that it would not happen again. That drive home last night was not fun at all.

Mister-B where in Salt Lake City are you located? I live down in Sandy.

10-08-2013, 01:24 PM	#1
Tachout Registered User Join Date: Oct 2013 Location: Sandy Utah Posts: 46	Breaking Question Today I drove my C20 to work for the first time. It is the factory Drum Brakes. It has been a while since I drove a vehicle with drum brakes. They leave a lot to be desired. Everything worked fine till I hit the offramp. The brake pedal got soft on me. I was on them pretty hard, but the pedal was soft and fading to the floor. I down shifted, and slowed down, and when I got around the off ramp corner, and down the hill I slowed down. Got pulled to a curb and as I stepped on the brakes they were normal again. Finished the 4 blocks and 2 turns to work and again the pedal was normal. Got out of the truck, came in to work, and got all set up. Went back down and checked the fluid. Fill and clear. I then checked the pedal and it feels normal. Could this have just been because they were hot, or is it time for a master cylinder? I do want to replace the brake hoses, and the battery and battery box this payday. If this needs a new master I will throw that on as well. This is a 1967 C30 with SBC and Manual Brakes.

10-08-2013, 02:47 PM	#2
Stocker 20' Daredevil (Ret) Join Date: May 2003 Location: Jefferson State Posts: 13,570	Re: Breaking Question Start by bleeding the brakes. If there's air in the lines and you get a soft pedal, you can often get a harder pedal by 'pumping' the brakes..... that is, pressing the pedal more than once. Kinda sounds like that's what happened to you, soft pedal then when you pressed it again it was better. Reading your post I didn't notice anything that would have caused the brakes to overheat, which of course would have caused decreased stopping power but the pedal should have still been hard if overheating was the problem. If bleeding doesn't fix it, try replacing the master cylinder. Fluid could be full, no air in system, but fluid bypassing internally. It's not uncommon. __________________ - Mike - 1972 K20 LWB 350/350/205 RIP El Jay

10-08-2013, 02:51 PM	#3
Tachout Registered User Join Date: Oct 2013 Location: Sandy Utah Posts: 46	Re: Breaking Question Thanks, it does not feel like air in the lines, and this was the only time I felt that soft pedal. I think to be on the safe side I have talked myself into a full front brake job, including a new master cylinder this weekend. Might just do te rears at the same time.

10-08-2013, 04:43 PM	#4
Lou Boffa Registered User Join Date: Jan 2013 Location: San Antonio, TX Posts: 733	Re: Breaking Question I got unassisted drums too. Even though I can lock the wheels with enough (a lot of) pressure, still scare the $#!^ out of me periodically. I got to get a booster added. That should help. __________________ Figure out what you want--then figure out what you are willing to give up to get it.

10-09-2013, 10:43 AM	#10
Tachout Registered User Join Date: Oct 2013 Location: Sandy Utah Posts: 46	Re: Breaking Question I looked at it last night and both front brake hoses are leaking. I suspect that is the root of the problem. The fluid looks rusty, and that is also not a good sign. I had considered that I could rebuild the one I have, along with rebuilding the wheel cylinders that I am sure could use a freshening, but to be honest the time it would take to get the kits, do the rebuild on the master (That I have done before seveal times) it is much less of a hassel to just bolt on the new parts, bleed everything and be done with it. Having all the rubber components replaced on something this old when it comes to stopping would give me peace of mind that it would not happen again. That drive home last night was not fun at all. Mister-B where in Salt Lake City are you located? I live down in Sandy.



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