I've got her to run, but need her to stop. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Blaze69 · 05-01-2003, 06:08 PM

Hi all,
Been awhile since I last posted, anyway here's my problem.
As I posted a while ago I was in the process of changing over to front disc on my '69. It took me a bit but I finally got it finished (somewhat). Here's what I've done so far:

1: swapped out the front end (that's a given), replaced the discs, pads, hoses, calipers and bearings.
2: bought new drums for the rear.
3. made new hoses (lines) to match the new setup.
4. Bled the **** out of the system, I now have clear fluid running to all the wheels.

What I didn't change was the booster or master cylinder.

My problem now is that when I got to stop I don't have any brakes on the first attempt. But, if I lightly pump the pedal the vehicle will damn near lock up.

I hope that someone out there can give me some advice on this matter. I would sure hate to have to take it into the shop and pay someone else for something I should fix.

Thanks.

**Palf70Step** · 05-01-2003, 06:12 PM

Sounds like master cylinder is going bad....plus since you now have discs..you should change to a disc brake master cylinder and proportioning valve...otherwise your brakes are going to be super erratic and may cr@p out alltogether at the most inconvient time.

SEVEND2 · 05-01-2003, 06:35 PM

I agree with Palf70step, cylinder and valve may need replacing.

**68 Stepside** · 05-01-2003, 08:38 PM

Nice Avatar

*Randy70C-10* · 05-01-2003, 08:52 PM

If you did all that work on the brake system, you should always change the master cylinder!! (cheap investment)

Blaze69 · 05-02-2003, 08:36 AM

When I changed over to the new system, I used the master cylinder and proportioning valve from the donor vehicle. You may be right and I'll have to try swapping in a new one.

One other thing.....the MC that I have now has two bleeder screws at the base (one for front and one for rear). When I went to the store to get a new one it didn't have the screws. Should this be a concern or not?

If all that has been said is true, then I still don't understand why the brakes would be so touchy. Is it because I have gotten used to the plush style of the new vehicles and lost my touch with the old school? Since I didn't replace the valve with a new one could that be the cause?? If not what other routes could I pursue???

Thanks again.....

05-01-2003, 06:08 PM	#1
Blaze69 Registered User Join Date: Apr 2001 Location: Arizona Posts: 147	I've got her to run, but need her to stop. Hi all, Been awhile since I last posted, anyway here's my problem. As I posted a while ago I was in the process of changing over to front disc on my '69. It took me a bit but I finally got it finished (somewhat). Here's what I've done so far: 1: swapped out the front end (that's a given), replaced the discs, pads, hoses, calipers and bearings. 2: bought new drums for the rear. 3. made new hoses (lines) to match the new setup. 4. Bled the ** out of the system, I now have clear fluid running to all the wheels. What I didn't change was the booster or master cylinder. My problem now is that when I got to stop I don't have any brakes on the first attempt. But, if I lightly pump the pedal the vehicle will damn near lock up. I hope that someone out there can give me some advice on this matter. I would sure hate to have to take it into the shop and pay someone else for something I should fix. Thanks. __________________ 1969 Blazer: 350/350, 4X4, HEI, Edlebrock carb/intake, dual flowmasters, np205, 3:07's and the rest is mostly stock. The front end disc swap is finally complete** 2002 Z71 Tahoe. CAI, Flowmaster 40, Silverstars in high, low and fogs and a bunch of mods (upgrades) inside and out.

05-01-2003, 06:12 PM	#2
Palf70Step State of Confusion! Join Date: Jul 2002 Location: Gulfport, MS USA Posts: 46,820	Sounds like master cylinder is going bad....plus since you now have discs..you should change to a disc brake master cylinder and proportioning valve...otherwise your brakes are going to be super erratic and may cr@p out alltogether at the most inconvient time. __________________ Bill 1970 Chevy Custom/10 LWB Fleetside 2010 Toyota Tacoma PreRunner SR5 Double Cab - DD Member of Louisiana Classic Truck Club (LCTC) Bill's Gallery Life isn't tied with a bow, but it's still a gift. Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God!

05-01-2003, 08:38 PM	#4
68 Stepside huh? Join Date: May 2000 Location: Washington, Illinois Posts: 5,692	Nice Avatar __________________ Someday when I'm lonely, Wishing you weren't so far away, Then I will remember Things we said today. RIP El Jay

05-02-2003, 08:36 AM	#6
Blaze69 Registered User Join Date: Apr 2001 Location: Arizona Posts: 147	When I changed over to the new system, I used the master cylinder and proportioning valve from the donor vehicle. You may be right and I'll have to try swapping in a new one. One other thing.....the MC that I have now has two bleeder screws at the base (one for front and one for rear). When I went to the store to get a new one it didn't have the screws. Should this be a concern or not? If all that has been said is true, then I still don't understand why the brakes would be so touchy. Is it because I have gotten used to the plush style of the new vehicles and lost my touch with the old school? Since I didn't replace the valve with a new one could that be the cause?? If not what other routes could I pursue??? Thanks again..... __________________ 1969 Blazer: 350/350, 4X4, HEI, Edlebrock carb/intake, dual flowmasters, np205, 3:07's and the rest is mostly stock. The front end disc swap is finally complete 2002 Z71 Tahoe. CAI, Flowmaster 40, Silverstars in high, low and fogs and a bunch of mods (upgrades) inside and out.

05-01-2003, 06:35 PM	#3
SEVEND2 Registered User Join Date: Aug 2001 Location: Menifee, Calif, USA Posts: 2,145	I agree with Palf70step, cylinder and valve may need replacing.

05-01-2003, 08:52 PM	#5
Randy70C-10 Account Suspended Join Date: Mar 2001 Location: Virginia Beach, Va. U.S.A. Posts: 15,320	If you did all that work on the brake system, you should always change the master cylinder!! (cheap investment)



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.