ABS Brake ? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Brainchild · 07-09-2006, 01:36 PM

Ok 96 Trans Sport has a brake problem.When you stomp on the pedal,it goes about halfway to the floor,and if you push it slowly it will go all the way to the floor.
So it sounds like the master cylinder to me,but it has ABS,and the guy that owns it says that the pump may be bad.So how do I check to see what I need to replace on this thing?
Any certain way to bleed the brakes,ect

Thanks

dwcsr · 07-09-2006, 05:25 PM

it sounds like a master to me also but plug the outlet ports on the master and try it again. what pump are you talking about? is it hydroboost?

Brainchild · 07-09-2006, 06:04 PM

Not hydroboost,the ABS pump,which is bolted to the master looks like on this van.
I haven't worked on an ABS brakesystem too much.The guy has replaced all the pads,shoes,front calipers,wheel cylinders,and one brake line trying to get the brakes fixed.It does have brakes sometimes,and then they just don't work.

So there again it sounds like the master.The ABS has no affect unless you under heavy braking is my understanding.So it would have no bearing on the function of the brakes under normal conditions,is this correct?

Do I have to have an ABS scan tool to bleed the brakes on this thing,I read on the net that I did,but I'm not for certain.I just don't want to get into something I don't have the tools to fix.

Thanks

Brainchild · 07-10-2006, 07:49 PM

Anyone?!?!

PBFAB.COM · 07-10-2006, 11:53 PM

Possibly the proportioning valve. Seen it before. How much pressure do you have at the rear calipers when bleeding? Crack the bleeder at the rear caliper, have somebody compress the brake pedal, see how much fluid shoots out. If it is a steady stream the proportioning valve should be OK, if it drizzles out real slow... BINGO. If the proportioning valve is built into the manifold block (for the ABS) take it to a qualified shop and get a second opinion... those manifolds are not cheap. Good Luck!

Brainchild · 07-11-2006, 12:25 AM

Thanks Porterbuilt,we can get fluid at either end,front or back,but not at the same time.

PBFAB.COM · 07-11-2006, 12:46 AM

Quote:

Originally Posted by Brainchild

Thanks Porterbuilt,we can get fluid at either end,front or back,but not at the same time.

Wierd... thought I was the lucky one who had all the stuff that nobody has ever heard about happen to!
When you figure out the problem let us all know.

Brainchild · 07-11-2006, 03:53 AM

OK Looking like a trip to the shop on this one.I'm begining to think I'll need the ABS scanner to get them to work.

07-09-2006, 01:36 PM	#1
Brainchild Still drivin' a Rat Rod Join Date: Sep 2004 Location: Monett Missouri Posts: 4,925	ABS Brake ? Ok 96 Trans Sport has a brake problem.When you stomp on the pedal,it goes about halfway to the floor,and if you push it slowly it will go all the way to the floor. So it sounds like the master cylinder to me,but it has ABS,and the guy that owns it says that the pump may be bad.So how do I check to see what I need to replace on this thing? Any certain way to bleed the brakes,ect Thanks __________________ Rusty Member #13872 Instead of saying.....you are a discomfort in the back of my front.....one should be able to say...... you are a pain in the a$# 71 GMC LWB 49 Chevy 85 Chevy G20 Check out my website

07-09-2006, 05:25 PM	#2
dwcsr Hollister Road Co. Join Date: Apr 2005 Location: Houston Posts: 6,131	Re: ABS Brake ? it sounds like a master to me also but plug the outlet ports on the master and try it again. what pump are you talking about? is it hydroboost?

07-09-2006, 06:04 PM	#3
Brainchild Still drivin' a Rat Rod Join Date: Sep 2004 Location: Monett Missouri Posts: 4,925	Re: ABS Brake ? Not hydroboost,the ABS pump,which is bolted to the master looks like on this van. I haven't worked on an ABS brakesystem too much.The guy has replaced all the pads,shoes,front calipers,wheel cylinders,and one brake line trying to get the brakes fixed.It does have brakes sometimes,and then they just don't work. So there again it sounds like the master.The ABS has no affect unless you under heavy braking is my understanding.So it would have no bearing on the function of the brakes under normal conditions,is this correct? Do I have to have an ABS scan tool to bleed the brakes on this thing,I read on the net that I did,but I'm not for certain.I just don't want to get into something I don't have the tools to fix. Thanks __________________ Rusty Member #13872 Instead of saying.....you are a discomfort in the back of my front.....one should be able to say...... you are a pain in the a$# 71 GMC LWB 49 Chevy 85 Chevy G20 Check out my website

07-10-2006, 07:49 PM	#4
Brainchild Still drivin' a Rat Rod Join Date: Sep 2004 Location: Monett Missouri Posts: 4,925	Re: ABS Brake ? Anyone?!?! __________________ Rusty Member #13872 Instead of saying.....you are a discomfort in the back of my front.....one should be able to say...... you are a pain in the a$# 71 GMC LWB 49 Chevy 85 Chevy G20 Check out my website

07-10-2006, 11:53 PM	#5
PBFAB.COM Senior Member Join Date: Dec 2003 Location: Mesa,Az Posts: 3,981	Re: ABS Brake ? Possibly the proportioning valve. Seen it before. How much pressure do you have at the rear calipers when bleeding? Crack the bleeder at the rear caliper, have somebody compress the brake pedal, see how much fluid shoots out. If it is a steady stream the proportioning valve should be OK, if it drizzles out real slow... BINGO. If the proportioning valve is built into the manifold block (for the ABS) take it to a qualified shop and get a second opinion... those manifolds are not cheap. Good Luck!

07-11-2006, 12:25 AM	#6
Brainchild Still drivin' a Rat Rod Join Date: Sep 2004 Location: Monett Missouri Posts: 4,925	Re: ABS Brake ? Thanks Porterbuilt,we can get fluid at either end,front or back,but not at the same time. __________________ Rusty Member #13872 Instead of saying.....you are a discomfort in the back of my front.....one should be able to say...... you are a pain in the a$# 71 GMC LWB 49 Chevy 85 Chevy G20 Check out my website

07-11-2006, 03:53 AM	#8
Brainchild Still drivin' a Rat Rod Join Date: Sep 2004 Location: Monett Missouri Posts: 4,925	Re: ABS Brake ? OK Looking like a trip to the shop on this one.I'm begining to think I'll need the ABS scanner to get them to work. __________________ Rusty Member #13872 Instead of saying.....you are a discomfort in the back of my front.....one should be able to say...... you are a pain in the a$# 71 GMC LWB 49 Chevy 85 Chevy G20 Check out my website



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