Does this booster/master set up look right? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Pont406 · 10-14-2007, 05:58 PM

I redid drum brakes all around with new hardware and wheel cylinders. Truck stops ok and straight. Only thing I can figure out is after driving it, master cylinder will get a drip of brake fluid. All I can think is that the angle its sitting at. Most pics that I seen dont have a bracket. Master is bolted to the firewall. Does this set up looks right or did PO hacked it?

70GMCer · 10-14-2007, 06:03 PM

That's the way these boosters are on these trucks. They lean forward. Check your brake cylinder gasket.

72hotrod · 10-14-2007, 06:05 PM

Don't know what you got, but that don't look right. Master cylinder should be tipped up in front. Definitely hacked. Maybe the bracket can be flipped?

**Boog** · 10-14-2007, 06:06 PM

Looks right to me. If it's leaking a bit out between the master cyl and booster the master needs to be replaced. It won't get any better. I see some rust on the face of the booster like brake fluid has been running down it and eating the paint off.

70GMCer · 10-14-2007, 06:22 PM

Quote:

Originally Posted by 72hotrod

Don't know what you got, but that don't look right. Master cylinder should be tipped up in front. Definitely hacked. Maybe the bracket can be flipped?

All the 67/72 trucks I've seen, have always been tilted forward (downward), including mine. Now the cars tilt back, (upward). Don't ask me why GM did this. I'm sure there was an engineering purpose for it. I'm sure others will chime in on this.....

xshadow · 10-14-2007, 06:27 PM

when you say master cylinder gets a drip. where is it leaking?

Pont406 · 10-14-2007, 08:09 PM

It's leaking right on the front. I took a pic with the srewdriver pointing to it. Now I know why I found a few brake fluid bottles in the truck when I got it.

**Boog** · 10-14-2007, 08:15 PM

Brake fluid leaks are bad. They aren't that expensive. Don't even try rebuilding that one. Reman units are too cheap.

Luvlegs · 10-14-2007, 08:41 PM

It all looks right to me (same as mine too) - I think you need to replace gasket on the top and that'll fix the problem (it looks like it's leaking all the way down to where you show the drip.

Bob 68327 · 10-14-2007, 10:26 PM

Looks like it should !!!!! change the master cylinder and your leak should go away !!! I have one also . The bracket is correct!!!!

aventur1 · 10-14-2007, 10:33 PM

Mine does not have the booster. Are there mounting holes already there for one?

EAST SIDE LOW LIFE · 10-14-2007, 11:06 PM

I have a 70' GMC and had a 71' Chevy SWB Fleet and both tilted down. My truck is lowered extreme no leaks. Check and see if M/S is filled at too high a level before you go changing things.

esll.

RustyParts · 10-15-2007, 08:03 AM

Here's a pic of the bracketry on my trucks booster. It's a 72 and the previous years may have been different.

68gmsee · 10-15-2007, 09:49 AM

Quote:

Originally Posted by 70GMCer

.... Don't ask me why GM did this. I'm sure there was an engineering purpose for it. I'm sure others will chime in on this.....

Could be that these trucks were made for hauling. That is, if the bed were loaded down, the truck would be lower in the back and the master cylinder would be more on the level side?????

Of course, these days, most of them are just used for cruising and occasional light hauling.

Re: the leak. It seems to be the back of the master cylinder as was mentioned already. The fluid could be creeping to the front from the bottom as noticed when the truck is not moving.

gonline71 · 10-15-2007, 12:11 PM

Looks to be at the same angle as mine.

My 71 does have an additional support bracket that runs to the firewall.

Based on the drip/wetness on the master cylinder, looks like your cap gasket is leaking.

I would replace that before doing anything else.

rick0312 · 10-15-2007, 02:51 PM

added a booster to my truck last year, they do not sit level, tend to lean toward the front. i would try a new seal and if that didn't work I replace the whole master cylinder.

xshadow · 10-15-2007, 09:04 PM

I agree with luvlegs. You can also see it in the first pic. It looks like it is leaking from the top. It looks like it's leaking from the top and running down to where the drip is

Quote:

Originally Posted by Luvlegs

It all looks right to me (same as mine too) - I think you need to replace gasket on the top and that'll fix the problem (it looks like it's leaking all the way down to where you show the drip.

chris71 · 10-16-2007, 09:07 AM

i replaced my original mc witha new one from the parts store wich has two wire holdowns, the originals have only one hold down, i feel that the new style ones hold the cap down tighter and more evenly. my old mc used to leak like crazy, now, not even a drop.

wpvtx · 10-16-2007, 11:50 PM

I had the same problem with the leak - start off by seeing if your brake pedal is adjusted right. If there is not a 1/8 to 1/4 of an inch of play it will not allow the master cylinder to return to the rest position and will cause a back pressure into the M/C and cause it to leak as shown - it couls also be the gasket but on mine it was the pedal adjustment. I hope this helps.

Morgsie · 10-17-2007, 01:52 AM

Quote:

Originally Posted by Pont406

I redid drum brakes all around with new hardware and wheel cylinders.

All that work, and you didn't change the master cylinder? Crazy.

10-14-2007, 05:58 PM	#1
Pont406 Registered User Join Date: Aug 2007 Location: West Hills, California Posts: 679	Does this booster/master set up look right? I redid drum brakes all around with new hardware and wheel cylinders. Truck stops ok and straight. Only thing I can figure out is after driving it, master cylinder will get a drip of brake fluid. All I can think is that the angle its sitting at. Most pics that I seen dont have a bracket. Master is bolted to the firewall. Does this set up looks right or did PO hacked it? Attached Images

10-14-2007, 06:03 PM	#2
70GMCer Senior Member Join Date: Apr 2005 Location: Joppa, Maryland Posts: 4,408	Re: Does this booster/master set up look right? That's the way these boosters are on these trucks. They lean forward. Check your brake cylinder gasket. __________________ 1997 GMC Sierra Ext 1965 Mustang

10-14-2007, 06:05 PM	#3
72hotrod Registered User Join Date: Mar 2004 Location: Red Chute,LA Posts: 62	Re: Does this booster/master set up look right? Don't know what you got, but that don't look right. Master cylinder should be tipped up in front. Definitely hacked. Maybe the bracket can be flipped?

10-14-2007, 06:06 PM	#4
Boog laying low Join Date: Mar 2001 Location: Searcy, Ark. USA Posts: 13,097	Re: Does this booster/master set up look right? Looks right to me. If it's leaking a bit out between the master cyl and booster the master needs to be replaced. It won't get any better. I see some rust on the face of the booster like brake fluid has been running down it and eating the paint off. __________________ Boog 69 Chevy stepside, 358/T350, 4.11 posi, 4.5/4 drop, rallys, poboy driver primer is finer 91 Chevy sportside, Tahoe, Yukon & GMC Crewcab All GM..'nuff said. I stand for the flag and kneel at the cross

10-14-2007, 06:27 PM	#6
xshadow Registered User Join Date: Apr 2006 Location: va Posts: 553	Re: Does this booster/master set up look right? when you say master cylinder gets a drip. where is it leaking?

10-14-2007, 08:09 PM	#7
Pont406 Registered User Join Date: Aug 2007 Location: West Hills, California Posts: 679	Re: Does this booster/master set up look right? It's leaking right on the front. I took a pic with the srewdriver pointing to it. Now I know why I found a few brake fluid bottles in the truck when I got it. Attached Images

10-14-2007, 08:15 PM	#8
Boog laying low Join Date: Mar 2001 Location: Searcy, Ark. USA Posts: 13,097	Re: Does this booster/master set up look right? Brake fluid leaks are bad. They aren't that expensive. Don't even try rebuilding that one. Reman units are too cheap. __________________ Boog 69 Chevy stepside, 358/T350, 4.11 posi, 4.5/4 drop, rallys, poboy driver primer is finer 91 Chevy sportside, Tahoe, Yukon & GMC Crewcab All GM..'nuff said. I stand for the flag and kneel at the cross

10-14-2007, 08:41 PM	#9
Luvlegs Registered User Join Date: Sep 2005 Location: Smith Mountain Lake Virginia Posts: 1,537	Re: Does this booster/master set up look right? It all looks right to me (same as mine too) - I think you need to replace gasket on the top and that'll fix the problem (it looks like it's leaking all the way down to where you show the drip. __________________ "A cat will almost always blink when hit between the eyes with a ball peen hammer" (you don't always have to state the obvious) Wear your PPE! You can eat with false teeth but you can't see with a false eye. 1959 Studebaker Silverhawk 350/400 1972 C10 L6 3OTT 2005 F350 - Built - whew!

10-14-2007, 10:26 PM	#10
Bob 68327 72 Chevelle Club Join Date: Jun 2007 Location: Newton , Iowa Posts: 2,052	Re: Does this booster/master set up look right? Looks like it should !!!!! change the master cylinder and your leak should go away !!! I have one also . The bracket is correct!!!! __________________ I Have The Right To Remain Silent,But Lack The Ability 1972 Chevelle ... Mine 2006 Trailblazer... Hers 2002 Buick century ... Kids 2002 K1500 Z-71 EXT CAB ... Daily Driver 2005 Rockwood Roo ... For Camping 1974 Harley-Davidson XLH Sportster 84'' stroker

10-14-2007, 10:33 PM	#11
aventur1 Registered User Join Date: Aug 2007 Location: Boise, Idaho Posts: 676	Re: Does this booster/master set up look right? Mine does not have the booster. Are there mounting holes already there for one?

10-14-2007, 11:06 PM	#12
EAST SIDE LOW LIFE Senior Member Join Date: Mar 2007 Location: VANCOUVER ISLAND, B.C., Canada Posts: 1,602	Re: Does this booster/master set up look right? I have a 70' GMC and had a 71' Chevy SWB Fleet and both tilted down. My truck is lowered extreme no leaks. Check and see if M/S is filled at too high a level before you go changing things. esll. Attached Images __________________ Tomorrow is for doing today's stuff. ************************************* This truck has just the right amount of energy for me! Author: Warren Lake .... (member) Last edited by EAST SIDE LOW LIFE; 10-15-2007 at 11:44 AM.

10-15-2007, 08:03 AM	#13
RustyParts Registered User Join Date: May 2006 Location: Wyman, Kentucky Posts: 403	Re: Does this booster/master set up look right? Here's a pic of the bracketry on my trucks booster. It's a 72 and the previous years may have been different. Attached Images __________________ 1972 GMC Jimmy, 4WD, 454 CI, 350 Turbo, 4" lift, 35" tires The math teacher said my son "Bubba" could be a mathmatical genius. cause he's got 13 fingers!

10-15-2007, 12:11 PM	#15
gonline71 Registered User Join Date: Jun 2007 Location: Pleasanton, CA Posts: 134	Re: Does this booster/master set up look right? Looks to be at the same angle as mine. My 71 does have an additional support bracket that runs to the firewall. Based on the drip/wetness on the master cylinder, looks like your cap gasket is leaking. I would replace that before doing anything else. Attached Images

10-15-2007, 02:51 PM	#16
rick0312 Registered User Join Date: Jan 2006 Location: Warrington, PA Posts: 403	Re: Does this booster/master set up look right? added a booster to my truck last year, they do not sit level, tend to lean toward the front. i would try a new seal and if that didn't work I replace the whole master cylinder.

10-16-2007, 09:07 AM	#18
chris71 Registered User Join Date: Oct 2007 Location: Sykesville MD Posts: 357	Re: Does this booster/master set up look right? i replaced my original mc witha new one from the parts store wich has two wire holdowns, the originals have only one hold down, i feel that the new style ones hold the cap down tighter and more evenly. my old mc used to leak like crazy, now, not even a drop. __________________ '55 3100 2nd series short-bed stepside '70 Corvette coupe stingray '71 Chevelle 2-dr coupe SS clone '71 C10 long-bed fleetside '83 long-haired brunette wife



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10-16-2007, 11:50 PM	#19
wpvtx Registered User Join Date: Apr 2007 Location: Burnsville MN Posts: 51	Re: Does this booster/master set up look right? I had the same problem with the leak - start off by seeing if your brake pedal is adjusted right. If there is not a 1/8 to 1/4 of an inch of play it will not allow the master cylinder to return to the rest position and will cause a back pressure into the M/C and cause it to leak as shown - it couls also be the gasket but on mine it was the pedal adjustment. I hope this helps. __________________ 1970 Chevy K10 350 CID with 4 speed 4" lift with 86 Dana 44 Front disk brakes Electric fan/Internal regulated Alt.

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