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

BadAssChevy502 · 10-14-2003, 05:51 AM

Brake help needed

I have a problem with my brakes every time when I first press the brakes I press them almost to the floor, if I then release it and press it again them I have full pressure this happens all the time and especially at low rpm’s when parking for instance.
Is this a booster problem or a master cylinder, proportioning valve or????

PLEASE help because these brakes are scaring the **** out off me, and I don’t know if ill be fast enough on a emergency situation

where I don’t have time enough to press it twice

INFO; 1972 Chevy ¾ ton pickup power brakes, front disc rear drum

**GMCPaul** · 10-14-2003, 06:01 AM

2 things I would consider first is there is air in the brake line and they need bled,or your steel brake lines are corroded or rubber lines are deteriorated and when you first step on the brake they swell to maximum size then second step on brake allows more fluid to moveto move brake cylinders & calipers. If its the last scenario your about to blow some brake lines.
GMCPaul

BadAssChevy502 · 10-14-2003, 06:07 AM

i have bled all the brakes and have no bad brake hoses as far as i can see,the steel brake lines i have to check again but i'm not loosing any fluid out off the master cylinder

**GMCPaul** · 10-14-2003, 06:15 AM

If its corroded lines swelling when pressure is applied you will not lose fluid until a line bursts or developes a small leak. In order to check the hoses for swelling have someone step on the brake while watching the hose to see if it enlarges.
GMCPaul

68 Suburban · 10-14-2003, 06:35 AM

The same thing was happening with my burb. It turned out to be the master cylinder. A trip to autozone and $11 later, it was as good as new.

BadAssChevy502 · 10-14-2003, 07:20 AM

New or repair kit ?????

BadAssChevy502 · 10-14-2003, 09:08 AM

Ok so the steel brake lines are good

, the rubber hoses are also good (not swelling up)

and it’s not leaking any brake fluid…………. What else can this be………..

!@#$%#$@!*&%$#@$

I’m going NUCKING FUTS

here (thanks to another board member for this translation LOL)

palallin · 10-14-2003, 09:19 AM

Replace the MC. Yours will eventually fail (and it sounds like that isn't far off). The result? Well, my pics are at home, so I'll have to post them later. . . . Trust me: it's unpleasant.

sneakysnake · 10-14-2003, 09:45 AM

Back shoes are not adjusting takes two pumps to reach the drum? Check to see how much play you have. Pull a drum check your shoes and run the adjuster out as far as you can,then after you put the drum on take a flat screw driver and run it out till you just start to hear or feel slight contact while spinning the wheel.

71GMC_3/4T · 10-14-2003, 11:00 AM

Sounds like the MC has a bad cup. There are two seal cups, one for front and one for rear.
If the front one is bad, you will have problems like you are describing. If the other is bad, you will lose brake fluid out the back end of the MC.
I'd go with new. Any I've rebuilt were rust pitted real bad and didn't last very long.

A.P. · 10-14-2003, 11:56 AM

I had the same the problem with my truck and it turn out to be the MC.

ckhd · 10-14-2003, 12:41 PM

There are several things that could cause that, most have been mentioned. I've been having the same problem with my '68 K20 for about two years now - tried a new M.C., checked balooning lines, bled like a crazed monkey, etc... I just fixed it yesterday.

Turns out that there was too much slack in the rear drums. I crawled under there and used a couple of screwdrivers and turned the auto adjusters like mad until there was a little bit of drag on the drum, then backed them off a little.

Amazing difference. I used to have to pump at LEAST once (usually twice) before I could get any braking action. Now, my pedal is firm and I can stop when I want.

Something to try before you start spending cash. Even though the master cylinder is very cheap (under $20 for a lifetime warranty one).

krue · 10-14-2003, 01:00 PM

I used to have a Mazda B2200 that I would adjust the brakes on and they would be tight as a drum, but the more I drove the more I would have to pump....turned out the back adjusters where on backwards!!! They were loosening everytime I stopped.

lukecp · 10-14-2003, 03:19 PM

I also think the master cylinder is the problem....only takes 1/2 an hour to install, and costs $20.

greasemonkey · 10-14-2003, 03:59 PM

lol krue, the dude before me put two short shoes on the left rear and two long shoes on the right rear.

BadAssChevy502 · 10-15-2003, 02:44 AM

Thanks all, I’ll go and check the rear brakes, and if that doesn’t work I’ll replace the MC

This board has been so helpful to me there should be an AWARD for best board or something

, I would definitely vote for this board, two thumbs up

BadAssChevy502 · 10-16-2003, 04:46 AM

...

JimKshortstep4x4 · 10-16-2003, 04:59 AM

Does the thumbs up mean your brakes are fixed?

Your 72 is a well optioned truck.

Jim

BadAssChevy502 · 10-16-2003, 06:32 AM

Thanks, JimKshortstep4x4 it sure is a well optioned Truck and I’m real happy with it ,but I still haven't located the brake problem so I'm going order A brand new MC ,but I was wondering about something, I can buy a repro non brand name MC for $49 and I can buy a original GM one for $110 what do you guys and gals think is there a difference between these two, my gut feeling tells me to get the GM one because I don’t want to play ”Russian roulette” with my brakes

Please Advice

BadAssChevy502 · 10-17-2003, 03:00 AM

any one

A.P. · 10-17-2003, 03:55 AM

I bought my from Chief Autoparts, now known as Autozone. That was a few years ago and I have not had any problems.

JimKshortstep4x4 · 10-17-2003, 06:52 AM

I have had very good luck with rebuilds from Autozone and other parts stores.

Jim

Adam12 · 10-18-2003, 04:15 PM

I just bought one 2 weeks ago from Pep boys for $15.99, I wouldnt spend $110 on one.

lukecp · 10-18-2003, 09:59 PM

I've got a $15 O'Reilly's MC in mine....been in there about a year and works great

Longhorn Man · 10-19-2003, 03:45 PM

I just noticed you are not in the states, that explains the huge frikken prices there.
You will be fine with the cheap parts. I see no reason to go with the GM one, I think it is just a chap part with there box wrapped around it.
If you know someone here in the states, you could probably get it cheaper by having him buy it and ship it to you. Seems people jack up the price exsesivly when dealing with over seas shipments.

10-14-2003, 05:51 AM	#1
BadAssChevy502 Yeh It's Fast Join Date: Sep 2003 Location: Zwijndrecht ,The Netherlands ,Europe Posts: 143	Brake help needed Brake help needed I have a problem with my brakes every time when I first press the brakes I press them almost to the floor, if I then release it and press it again them I have full pressure this happens all the time and especially at low rpm’s when parking for instance. Is this a booster problem or a master cylinder, proportioning valve or???? PLEASE help because these brakes are scaring the **** out off me, and I don’t know if ill be fast enough on a emergency situation where I don’t have time enough to press it twice INFO; 1972 Chevy ¾ ton pickup power brakes, front disc rear drum __________________ (I'm sorry if the spelling isn't correct,i'm trying the best I can ) 1972 C20 3/4 Pickup Fleetside 502ci Th400 Click here to view pictures of my truck 1971 C20 3/4 Pickup Fleetside 350ci 3speed manual gearbox "IF IT AIN'T BROKE DON'T TRY TO FIX IT" Zwijndrecht, The Netherlands Europe

10-14-2003, 06:01 AM	#2
GMCPaul Senior Member Join Date: Mar 2000 Location: Rockville,In. USA Posts: 3,721	2 things I would consider first is there is air in the brake line and they need bled,or your steel brake lines are corroded or rubber lines are deteriorated and when you first step on the brake they swell to maximum size then second step on brake allows more fluid to moveto move brake cylinders & calipers. If its the last scenario your about to blow some brake lines. GMCPaul __________________ Secure Online Catalog for-GMCPauls Truck Parts Email- GMCPAULS@GMAIL.COM

10-14-2003, 06:07 AM	#3
BadAssChevy502 Yeh It's Fast Join Date: Sep 2003 Location: Zwijndrecht ,The Netherlands ,Europe Posts: 143	Thanks for your help i have bled all the brakes and have no bad brake hoses as far as i can see,the steel brake lines i have to check again but i'm not loosing any fluid out off the master cylinder __________________ (I'm sorry if the spelling isn't correct,i'm trying the best I can ) 1972 C20 3/4 Pickup Fleetside 502ci Th400 Click here to view pictures of my truck 1971 C20 3/4 Pickup Fleetside 350ci 3speed manual gearbox "IF IT AIN'T BROKE DON'T TRY TO FIX IT" Zwijndrecht, The Netherlands Europe

10-14-2003, 06:15 AM	#4
GMCPaul Senior Member Join Date: Mar 2000 Location: Rockville,In. USA Posts: 3,721	If its corroded lines swelling when pressure is applied you will not lose fluid until a line bursts or developes a small leak. In order to check the hoses for swelling have someone step on the brake while watching the hose to see if it enlarges. GMCPaul __________________ Secure Online Catalog for-GMCPauls Truck Parts Email- GMCPAULS@GMAIL.COM

10-14-2003, 06:35 AM	#5
68 Suburban Registered User Join Date: Oct 2000 Location: From Chicago, Live in Phoenix, AZ Posts: 6,802	The same thing was happening with my burb. It turned out to be the master cylinder. A trip to autozone and $11 later, it was as good as new. __________________ Just sitting here contemplating contemplation.

10-14-2003, 07:20 AM	#6
BadAssChevy502 Yeh It's Fast Join Date: Sep 2003 Location: Zwijndrecht ,The Netherlands ,Europe Posts: 143	New or repair kit ????? New or repair kit ????? __________________ (I'm sorry if the spelling isn't correct,i'm trying the best I can ) 1972 C20 3/4 Pickup Fleetside 502ci Th400 Click here to view pictures of my truck 1971 C20 3/4 Pickup Fleetside 350ci 3speed manual gearbox "IF IT AIN'T BROKE DON'T TRY TO FIX IT" Zwijndrecht, The Netherlands Europe

10-14-2003, 09:08 AM	#7
BadAssChevy502 Yeh It's Fast Join Date: Sep 2003 Location: Zwijndrecht ,The Netherlands ,Europe Posts: 143	dunno anymore Ok so the steel brake lines are good , the rubber hoses are also good (not swelling up) and it’s not leaking any brake fluid…………. What else can this be……….. !@#$%#$@!*&%$#@$ I’m going NUCKING FUTS here (thanks to another board member for this translation LOL) __________________ (I'm sorry if the spelling isn't correct,i'm trying the best I can ) 1972 C20 3/4 Pickup Fleetside 502ci Th400 Click here to view pictures of my truck 1971 C20 3/4 Pickup Fleetside 350ci 3speed manual gearbox "IF IT AIN'T BROKE DON'T TRY TO FIX IT" Zwijndrecht, The Netherlands Europe

10-14-2003, 09:19 AM	#8
palallin Registered User Join Date: Jul 2002 Location: St. James, MO Posts: 1,238	Replace the MC. Yours will eventually fail (and it sounds like that isn't far off). The result? Well, my pics are at home, so I'll have to post them later. . . . Trust me: it's unpleasant. __________________ '69 Longstep K-10: 327/SM465/T-221/Closed Knuckle Dana44/12-bolt.

10-14-2003, 09:45 AM	#9
sneakysnake It's a catastrophic success. Join Date: Jan 2003 Location: Oklahoma Posts: 2,077	Back shoes are not adjusting takes two pumps to reach the drum? Check to see how much play you have. Pull a drum check your shoes and run the adjuster out as far as you can,then after you put the drum on take a flat screw driver and run it out till you just start to hear or feel slight contact while spinning the wheel.

10-14-2003, 11:00 AM	#10
71GMC_3/4T Weapons Of Construction Join Date: Apr 2000 Location: Colorado, USA Posts: 1,095	Sounds like the MC has a bad cup. There are two seal cups, one for front and one for rear. If the front one is bad, you will have problems like you are describing. If the other is bad, you will lose brake fluid out the back end of the MC. I'd go with new. Any I've rebuilt were rust pitted real bad and didn't last very long. __________________ 1971 GMC 2500, 402/TH400 4.10 Daily Driver Lafayette, CO

10-14-2003, 11:56 AM	#11
A.P. Black 72 Chevy Join Date: May 2002 Location: Los Angeles, California Posts: 662	I had the same the problem with my truck and it turn out to be the MC. __________________ 72 Chevy, SWB, 350engine, TH400

10-14-2003, 12:41 PM	#12
ckhd Registered User Join Date: Oct 2000 Location: St. Johns, Arizona Posts: 2,660	There are several things that could cause that, most have been mentioned. I've been having the same problem with my '68 K20 for about two years now - tried a new M.C., checked balooning lines, bled like a crazed monkey, etc... I just fixed it yesterday. Turns out that there was too much slack in the rear drums. I crawled under there and used a couple of screwdrivers and turned the auto adjusters like mad until there was a little bit of drag on the drum, then backed them off a little. Amazing difference. I used to have to pump at LEAST once (usually twice) before I could get any braking action. Now, my pedal is firm and I can stop when I want. Something to try before you start spending cash. Even though the master cylinder is very cheap (under $20 for a lifetime warranty one). __________________ my 2¢ - t.i.o.l.i. Bowen 1968 K20 fleet 1969 K10 swb fleet 1972 K10 Suburban 1972 C10 lwb step 1992 K1500 'burb 1995 K2500 'burb 1997 C1500 'burb 1999 K1500 2000 K1500 'burb Why do I own so many Suburbans?

10-14-2003, 01:00 PM	#13
krue Designated A-hole! Join Date: Mar 2003 Location: South Mississippi Posts: 36,448	I used to have a Mazda B2200 that I would adjust the brakes on and they would be tight as a drum, but the more I drove the more I would have to pump....turned out the back adjusters where on backwards!!! They were loosening everytime I stopped. __________________ "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"

10-14-2003, 03:19 PM	#14
lukecp Formerly yellow72custom Join Date: May 2001 Location: Austin, TX Posts: 7,531	I also think the master cylinder is the problem....only takes 1/2 an hour to install, and costs $20. __________________ '72 Chevy C10 Mild 350/TH350/3.07. Ochre/White. Old high school ride. '70 GMC C2500 '62 327 4bbl/SM465/4.56-geared Dana 60. White/White. Project or parts truck. '97 Saturn SL DD. 1.9/5-speed. 40+ highway mpg

10-14-2003, 03:59 PM	#15
greasemonkey Registered User Join Date: Dec 2001 Location: Pace, FL Posts: 2,155	lol krue, the dude before me put two short shoes on the left rear and two long shoes on the right rear. __________________ 1942 Master Deluxe 1969 C/10 1985 Blazer CUCV 1987 Jimmy 2004 Tahoe 2005 Silverado 1500 2005 Silverado 3500



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10-15-2003, 02:44 AM	#16
BadAssChevy502 Yeh It's Fast Join Date: Sep 2003 Location: Zwijndrecht ,The Netherlands ,Europe Posts: 143	Thanks all Thanks all, I’ll go and check the rear brakes, and if that doesn’t work I’ll replace the MC This board has been so helpful to me there should be an AWARD for best board or something , I would definitely vote for this board, two thumbs up __________________ (I'm sorry if the spelling isn't correct,i'm trying the best I can ) 1972 C20 3/4 Pickup Fleetside 502ci Th400 Click here to view pictures of my truck 1971 C20 3/4 Pickup Fleetside 350ci 3speed manual gearbox "IF IT AIN'T BROKE DON'T TRY TO FIX IT" Zwijndrecht, The Netherlands Europe

10-16-2003, 04:46 AM	#17
BadAssChevy502 Yeh It's Fast Join Date: Sep 2003 Location: Zwijndrecht ,The Netherlands ,Europe Posts: 143	... ... __________________ (I'm sorry if the spelling isn't correct,i'm trying the best I can ) 1972 C20 3/4 Pickup Fleetside 502ci Th400 Click here to view pictures of my truck 1971 C20 3/4 Pickup Fleetside 350ci 3speed manual gearbox "IF IT AIN'T BROKE DON'T TRY TO FIX IT" Zwijndrecht, The Netherlands Europe

10-16-2003, 04:59 AM	#18
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Does the thumbs up mean your brakes are fixed? Your 72 is a well optioned truck. Jim

10-16-2003, 06:32 AM	#19
BadAssChevy502 Yeh It's Fast Join Date: Sep 2003 Location: Zwijndrecht ,The Netherlands ,Europe Posts: 143	Thanks, JimKshortstep4x4 Thanks, JimKshortstep4x4 it sure is a well optioned Truck and I’m real happy with it ,but I still haven't located the brake problem so I'm going order A brand new MC ,but I was wondering about something, I can buy a repro non brand name MC for $49 and I can buy a original GM one for $110 what do you guys and gals think is there a difference between these two, my gut feeling tells me to get the GM one because I don’t want to play ”Russian roulette” with my brakes Please Advice __________________ (I'm sorry if the spelling isn't correct,i'm trying the best I can ) 1972 C20 3/4 Pickup Fleetside 502ci Th400 Click here to view pictures of my truck 1971 C20 3/4 Pickup Fleetside 350ci 3speed manual gearbox "IF IT AIN'T BROKE DON'T TRY TO FIX IT" Zwijndrecht, The Netherlands Europe

10-17-2003, 03:00 AM	#20
BadAssChevy502 Yeh It's Fast Join Date: Sep 2003 Location: Zwijndrecht ,The Netherlands ,Europe Posts: 143	no one any one __________________ (I'm sorry if the spelling isn't correct,i'm trying the best I can ) 1972 C20 3/4 Pickup Fleetside 502ci Th400 Click here to view pictures of my truck 1971 C20 3/4 Pickup Fleetside 350ci 3speed manual gearbox "IF IT AIN'T BROKE DON'T TRY TO FIX IT" Zwijndrecht, The Netherlands Europe

10-17-2003, 03:55 AM	#21
A.P. Black 72 Chevy Join Date: May 2002 Location: Los Angeles, California Posts: 662	I bought my from Chief Autoparts, now known as Autozone. That was a few years ago and I have not had any problems.

10-17-2003, 06:52 AM	#22
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	I have had very good luck with rebuilds from Autozone and other parts stores. Jim

10-18-2003, 04:15 PM	#23
Adam12 I hate trannys Join Date: Dec 2001 Location: Bakersfield,CA Posts: 160	I just bought one 2 weeks ago from Pep boys for $15.99, I wouldnt spend $110 on one. __________________ 70 SWB 481 ci, TH-400, Edlebrok Victor Jr. intake, Holley street avenger 770, Dynomax ceramic coated headers. Dual flowmasters. and only 3516134 more little things to do.

10-18-2003, 09:59 PM	#24
lukecp Formerly yellow72custom Join Date: May 2001 Location: Austin, TX Posts: 7,531	I've got a $15 O'Reilly's MC in mine....been in there about a year and works great __________________ '72 Chevy C10 Mild 350/TH350/3.07. Ochre/White. Old high school ride. '70 GMC C2500 '62 327 4bbl/SM465/4.56-geared Dana 60. White/White. Project or parts truck. '97 Saturn SL DD. 1.9/5-speed. 40+ highway mpg

10-19-2003, 03:45 PM	#25
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	I just noticed you are not in the states, that explains the huge frikken prices there. You will be fine with the cheap parts. I see no reason to go with the GM one, I think it is just a chap part with there box wrapped around it. If you know someone here in the states, you could probably get it cheaper by having him buy it and ship it to you. Seems people jack up the price exsesivly when dealing with over seas shipments.

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