On my 86 Trans Am I have the 4 wheel disc brakes from the factory. Great stopping power for everyday driving and a little back roads performance.
Though lately actually for a while now they won't lock up, feel a little spongy and I have to push the brake pedel almost the whole way to the floor to get them to hit with any power.
Is this a bad brake booster? Calipers? I shouldn't need ne pads and Rotors yet. I think they have only like 10,000 or 15,000 miles on them. No those miles have not been that hard either.
So whats your ideas guys?
Also if you know what the problem is, what can I do to fix it and how hard is it?

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86 Trans Am 355 TPI Rebuilt 700R4 with Corvette servo, modified valve body, and a B&M Torque Converter (2000 rpm stall w/ lock up), 87 350 block bored .30 with new crank. Reworked 305 heads with 3-angle valve job. Added in the rebuild was an SLP TPI cam, BBK 58mm Throttle Body,MSD 6A, Hypertech Power Coil, 1.5 Crane roller tipped rocker arms, SLP Intake Runners and Port matching in upper intake including fully ported plenum, TPIS adjustable fuel pressure regulator @ 46psi, Hooker shorty style headers w/ Thermotech heat wrapping, Custom 3” exhaust with Flowmaster muffler and chrome quad tips, Hypertech Thermomaster Computer chip, K&N open element cone filter on modified MAF per TPIS specs, MSD Wires, removal of A/C hardware and added a 1LE firewall cover installed. Also there has been a PST front suspension kit with Hotchkis strut tower brace added. Soon to have Intrax lowering springs.
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Kills:
95 Talon TSI, 96 Probe GT, 91 T/A L98, 89 RS, 86 Mustang GT, 88 Mustang LX 5.0, 92 Thunderbird V8. couple or ricers that I think were Civics or Preludes not sure what year, 95 Celica GT-S, 94 Chevy 1/4 ton 350, one of those NASCAR F150's

The Third Gen Will Never be Forgotten

 

anyone????? Please help me

 

I noticed a HUGE difference when I changed to the stainless hosses and new brake fluid. I also changed to the Z-rated Performance Friction brake pads, probably the biggest help. Also another thought, check the rear calipers, they have been known to go south quite often.

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'86 TA, T-tops, T-5, 3.73, 4 wheel disks 350, compucam 2040, performer intake,SLP Headers, 3" race magnum muffler, 1.6 Comp rockers, Ripper shifter, perf. friction pads, Hypertech ignition, Earls brake hoses, Hotchkis springs, Tokico Illumina 5 adjustable shocks and struts, Lakewood panhard and trailing arms
14.73 @ 95... traction still a problem

 

How is your brake rotors...I had brake problems with my 4 wheel disc brakes and once I replaced the worn rotors it was pretty much fixed. Just a thought..
Darrell

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1991 GTA L98
K&N Filter, Subframe Connectors, 3.73 Gears, Hypertech Airfoil, Ported Plenum, Underdrive Pulleys, Flowmaster Catback, no cats, Hypertech AFPR,Ed Wright Stage I Fastchip, and a 160 Thermostat.

 

Ok the Calipers on the back are good. Nice clean lines on rotors, even wear, and no rust forming so I know they are wroking. Rotors have less than 20,000 miles on them all the way around. Also has new brake hoses on the rear.(Just the rubber ones)
This is something that has gotten worse over time.
Keep the ideas coming guys, someone will eventually hit something I haven't checked yet or have a reason why its doing this.
Thanks

 

Internally leaking m/c
Cracked rear brake hoses letting air in


[This message has been edited by TomP (edited March 02, 2001).]

 

I don't know abou the master Cyl., but there is new brake hoses on the rear, so I doubt they are the problem, but I am going to give them a good inspection tonight.

 

The rear calipers need to be adjusted using the parking brake frequently. If you havent done that they may be out of adjustment. Although you did say the rear rotors are clean.

Just a thought, you never know
I've been battling the problem ever since i installed a disc rear

Is you "brake" light on?

 

Every now and then the light comes on.
Upon inspection this weekend, no leaks hoses front and back look good still pedal feels mushy?
What now

 

Bleed the brakes to check for any air in the system.

Check the adjustment of the rear calipers. Because of how the park brake works, the rear calipers need to be occasionally adjusted.

If neither of those fixes the problem then you have a bad master cylinder. Pressure is leaking past the piston seals internally.

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87 IROC-Z Pro ET Bracket Race Car
383 stroker (carbed) with double hump cast iron heads and pump gas
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Best results before the 383 blew up
Best ET on a time slip: 11.857 altitude corrected to 11.163
Best MPH on a time slip: 117.87 altitude corrected to 126.10
Altitude corrected rear wheel HP based on power to weight ratio: 476.5
Best 60 foot: 1.662

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87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley

 

OK will do. So none of this sounds like the brake booster huh.
What does it feel like when the booster goes bad?

 

It'll be harder to stop than having manual brakes

 

It definitely sounds like an internally leaking master cylinder. I had the same problem, the light would go on but the brakes still worked but with a spongy pedal. $29.99 later my brakes work like new.

 

It definitely sounds like an internally leaking master cylinder. I had the same problem, the light would go on but the brakes still worked but with a spongy pedal. $29.99 later my brakes work like new.

 

If it's a leaking booster, you will hear a hissing when you keep the pedal pressed and the brakes will be hard and weak. It doesn't happen often, but I had to replace the booster on a '91 Cavalier. If that's the case, get one from a wrecking yard. New ones cost a fortune from The General.

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1985 Yellow IROC-Z 5.0 HO, T-5 3.73 Posi, 4 wheel disks
PFCM pads, GTA wheels, Koni yellows, B&M Ripper, Dynomax

 

Just a bit of advice: don't rule out any part being the problem just because it's new.