Need Help.... Braking is poor! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Russ72C10 · 08-21-2004, 01:38 AM

I've got an 84 3/4 4x4... Front disc.. rear drum. I've had the rotors turned, new pads, new driver side caliper (old one seized up) & brake hose (replaced this before the caliper) . Essentially, even if I slam on the brakes, it won't come to a rapid stop, nor even lock up the tires and skid. The pedal has decent feel... the fronts have been bled repeatedly. I can't bleed the rears as the bleed screws are stripped & will have to be drilled out (which I plan on doing fairly soon).

At any rate, tonight while coming up on an intersection, the light changed and I was probably 200ft back or so. Plenty of time to stop from 35mph - or so I thought. I put the pedal to the floor... the truck comes to a slow halt about 15ft out in the intersection. Not good. I've never had to use the brakes so hard before, so I'm not sure if it's always been this way or if it's a recent problem.

Does anyone have ideas as to what could cause this? A couple of buddies said a check-valve controlling vacuum to the brake booster could be bad? Or since I lifted the truck 4" the height-sensing proportional valve could be screwing up the front-to-rear braking bias? Or my new pads (WearEver - Advance AutoParts) could suck? Or...... ???? I'm looking for ideas... I don't have a lot of $$$ to chase this problem... so I'll go with what sounds most likely for starters!

Thanks a lot! I really appreciate any help you guys (and gals) may provide!

74Pumpkin · 08-21-2004, 10:06 AM

You could have a defective booster. When a power booster goes bad, the pedel will get extremely hard. Its like stepping on a brick! to check your booster, Turn off the engine and step on the pedel five to six times to empty the booster. Put your foot on the brake pedal with moderate pressure, and start the engine. Your foot should fall slightly. If not, Your booster is bad.

Another possable reason is a restriction in the vacume line or in the booster check valve since the booster wil not be able to replenish the vacume fast enough.

Possably a frozen wheel cylinder. A drum brake will feel very hard since the fluid cannot travel anywhere under pressure.

I think you should first fix the rear bleeders before you go crazy trying to find another reason. You might be able to save yourself some hassel and headach if you start there.

Just so happens this months Classic Trucks had an article dealing with this very subject in it. Hope it helps!

cliffsta · 08-21-2004, 01:44 PM

hmmm, checked your master cylinder? my truck has had a billion master cylinders b/c the replacement master cylinders suck.

Senor_paco · 08-21-2004, 03:04 PM

Quote:

Originally Posted by cliffsta

hmmm, checked your master cylinder? my truck has had a billion master cylinders b/c the replacement master cylinders suck.

Same here. Iany times I bled the system, replaced parts, turns out the cylinder was bad. oh well, I have all new parts an braided steel lines now. If I hit the brakes too hard now, I risk detaching my retinas.

cliffsta · 08-21-2004, 06:42 PM

heh heh!! yeah i've only been driving ol red since april, so im afraid of the time i go to get on the brakes and nothing happens; kinda hard to bring a gigantic metal brick to a stop without brakes. my dad has said it has happened before.

Russ72C10 · 08-21-2004, 09:15 PM

Well, I crawled under it tonight to take a look around. Turns out my rear right brake line had a crack in it near the wheel cylinder. Fluid was slowly trickling down the wheel... very slowly. So I tore the lines out of the back & vise-gripped out the seized up bleeder screws. Should have it all replaced and bled back out soon.... maybe that was the problem? Sure couldn't have helped anything! Will report back.....

Edit : Wanted to add my "findings" to this thread in case anyone else has a similar problem in the future. It ended up being the 'leak' at the rear brake line. I replaced both lines & bleeders - bled the rear brakes.... took 'er for a spin. PROBLEM SOLVED! Sucker stops like it should now.

08-21-2004, 01:38 AM	#1
Russ72C10 Four Wheeler Join Date: Jul 2002 Location: Decatur, IL Posts: 101	Need Help.... Braking is poor! I've got an 84 3/4 4x4... Front disc.. rear drum. I've had the rotors turned, new pads, new driver side caliper (old one seized up) & brake hose (replaced this before the caliper) . Essentially, even if I slam on the brakes, it won't come to a rapid stop, nor even lock up the tires and skid. The pedal has decent feel... the fronts have been bled repeatedly. I can't bleed the rears as the bleed screws are stripped & will have to be drilled out (which I plan on doing fairly soon). At any rate, tonight while coming up on an intersection, the light changed and I was probably 200ft back or so. Plenty of time to stop from 35mph - or so I thought. I put the pedal to the floor... the truck comes to a slow halt about 15ft out in the intersection. Not good. I've never had to use the brakes so hard before, so I'm not sure if it's always been this way or if it's a recent problem. Does anyone have ideas as to what could cause this? A couple of buddies said a check-valve controlling vacuum to the brake booster could be bad? Or since I lifted the truck 4" the height-sensing proportional valve could be screwing up the front-to-rear braking bias? Or my new pads (WearEver - Advance AutoParts) could suck? Or...... ???? I'm looking for ideas... I don't have a lot of $$$ to chase this problem... so I'll go with what sounds most likely for starters! Thanks a lot! I really appreciate any help you guys (and gals) may provide! __________________ '84 K20 4x4 350 V8 - Weiand intake - Headers - 4" Tuff Country lift - 35x12.50 ProComp M/Ts on 15x10s Last edited by Russ72C10; 08-21-2004 at 01:47 AM.

08-21-2004, 10:06 AM	#2
74Pumpkin Insert witty comment here Join Date: Nov 2003 Location: Lakeville Minnesota Posts: 388	You could have a defective booster. When a power booster goes bad, the pedel will get extremely hard. Its like stepping on a brick! to check your booster, Turn off the engine and step on the pedel five to six times to empty the booster. Put your foot on the brake pedal with moderate pressure, and start the engine. Your foot should fall slightly. If not, Your booster is bad. Another possable reason is a restriction in the vacume line or in the booster check valve since the booster wil not be able to replenish the vacume fast enough. Possably a frozen wheel cylinder. A drum brake will feel very hard since the fluid cannot travel anywhere under pressure. I think you should first fix the rear bleeders before you go crazy trying to find another reason. You might be able to save yourself some hassel and headach if you start there. Just so happens this months Classic Trucks had an article dealing with this very subject in it. Hope it helps! __________________ So many trucks, So little time!

08-21-2004, 01:44 PM	#3
cliffsta Stepsides RULE Join Date: Jul 2004 Location: Pineville, LA Posts: 1,921	hmmm, checked your master cylinder? my truck has had a billion master cylinders b/c the replacement master cylinders suck. __________________ 1981 Chevy C10 Custom Deluxe Stepside 350 V8, headers, side exhausts, 3-speed auto SOLD 1980 Chevy C10 Custum Deluxe Stepside 305 V8, Edelbrock Performer Intake, Edelbrock 1406 600CFM 4-barrel, TH350C. Bent rod. SOLD 1984 GMC Sierra Classic Longbed 6.2L Diesel SOLD 2009 Kawasaki KLX-250S too many mods for this signature 1999 Honda Accord EX 4-cylinder, 17" Motegi Wheels 215/45/17 Sumitomo tires, Tein S-Tech lowering springs, KYB GR2 shocks, Acura TL 20mm rear swaybar, debadged, blackhoused headlights, Short-Ram Intake Cardomain of the Accord

08-21-2004, 06:42 PM	#5
cliffsta Stepsides RULE Join Date: Jul 2004 Location: Pineville, LA Posts: 1,921	heh heh!! yeah i've only been driving ol red since april, so im afraid of the time i go to get on the brakes and nothing happens; kinda hard to bring a gigantic metal brick to a stop without brakes. my dad has said it has happened before. __________________ 1981 Chevy C10 Custom Deluxe Stepside 350 V8, headers, side exhausts, 3-speed auto SOLD 1980 Chevy C10 Custum Deluxe Stepside 305 V8, Edelbrock Performer Intake, Edelbrock 1406 600CFM 4-barrel, TH350C. Bent rod. SOLD 1984 GMC Sierra Classic Longbed 6.2L Diesel SOLD 2009 Kawasaki KLX-250S too many mods for this signature 1999 Honda Accord EX 4-cylinder, 17" Motegi Wheels 215/45/17 Sumitomo tires, Tein S-Tech lowering springs, KYB GR2 shocks, Acura TL 20mm rear swaybar, debadged, blackhoused headlights, Short-Ram Intake Cardomain of the Accord

08-21-2004, 09:15 PM	#6
Russ72C10 Four Wheeler Join Date: Jul 2002 Location: Decatur, IL Posts: 101	Well, I crawled under it tonight to take a look around. Turns out my rear right brake line had a crack in it near the wheel cylinder. Fluid was slowly trickling down the wheel... very slowly. So I tore the lines out of the back & vise-gripped out the seized up bleeder screws. Should have it all replaced and bled back out soon.... maybe that was the problem? Sure couldn't have helped anything! Will report back..... Edit : Wanted to add my "findings" to this thread in case anyone else has a similar problem in the future. It ended up being the 'leak' at the rear brake line. I replaced both lines & bleeders - bled the rear brakes.... took 'er for a spin. PROBLEM SOLVED! Sucker stops like it should now. __________________ '84 K20 4x4 350 V8 - Weiand intake - Headers - 4" Tuff Country lift - 35x12.50 ProComp M/Ts on 15x10s Last edited by Russ72C10; 08-25-2004 at 01:26 AM.



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