Help! Kelsey-Hayes ABS
 

I read and tried everything to bleed the beast and can’t get rid of the spongy pedal! What does it take to get the job done?

Re: Help! Kelsey-Hayes ABS
 

There's a little $20 J-tool that clips on the nub under that rubber cap in the pic. It seems insignificant but that's what it needs to do the job. I replaced the pump and master cyl. in this pic on my K2500.

ABS units on GMT400 can only be dealt with one way
 

Even though I owned a Solus pro scanner and a complete GM shop manual, I never searched for any information regarding ABS bleeding.

I even wrote up a procedure on changing the master cylinder to a different year to over come the problem you are speaking of. It wasn't until years later that I came across a write up concerning the "Automatic Bleed" process.

Up to that point, my feeling was the ABS has nothing to do with the feel of the brakes under normal circumstances so bleeding it should have nothing to do with the normal brake feel. I was completely wrong. If you google it, you will read post after post of people that have discovered their brakes were never as good as when they did the automatic bleed.

The automatic bleed process is a procedure done with a scanner that bleeds the ABS unit by itself and only requires the user to hold the brake pedal down. It's hard to describe until you actually witness it during the process. It takes about 2 minutes to do but again it requires certain "scanners" to do it. It will pump up and release the pedal while the process is happening.

The GM shop manual says to bleed the entire brake system like you would normally do a system that does NOT have ABS. You know the drill, right rear first, then left rear then right front and lastly left front.

The manual says to do the "automatic bleed" process and follow it up with another complete old time system bleed.

Everything I had done to this point has been a band aid to poor pedal feel. It wasn't until I did the automatic bleed process that the pedal came back to a good quality feel and stopping capability.

Some (one in particular) will argue this does nothing. However, I can state it does and several on many websites it did for them.

If you don't have access to a scanner that has the capability, talk to a shop in your area and ask them how much they would charge to hook up and do the process. You could do your own regular bleed, take it to the shop and have them do the automatic bleed and bring it back home to do the last bleed.

Most private shops have a set fee for hooking up to the diagnostic port. This should not be much at all. I would expect about $50 + - .

For comparison sake, you could ask the dealer what they charge for the process NOT including the physical bleeding process.

Remember that you need good pads/shoes in place, properly functioning calipers/wheel cylinders and clean brake fluid that is bled correctly.

There is a process to bleed the brakes that does NOT require 2 people and does not use elaborate tools. It employs a clear bottle, tubing, the correct size wrench and some brake fluid. It works every time, by yourself.

I'd be interested in your results after the process is done correctly. Good luck.

Re: Help! Kelsey-Hayes ABS
 

What about pressure bleeding from the MC down?

Re: ABS units on GMT400 can only be dealt with one way
 

Thanks for posting this. I’ve bled the brakes on my 97 a half dozen times because of rusted and blown steel brake lines and have tolerated the spongy brake pedal feel.

Paul

Re: Help! Kelsey-Hayes ABS
 

Found this today...

https://www.youtube.com/watch?v=fUqmBqYIEAE

I am planning on getting one because I had to replace some brake lines recently.

Also from what I am seeing Foxwell NT630 Pro also has a Autobleed function.

Plus I have seen where unhooking the batteries for 30min-1hour then bleed like an other car.
He was pretty adamant this would work.

The Foxwell NT630 Pro is just over $100, I think I'd like something to read codes anyway.

Re: Help! Kelsey-Hayes ABS
 

Great find! I need to research this scanner a little more and see if it will do wheel time ABS data. The ABS on my 97 is on the fritz again.

Any recommendations on scan tools? The one in the video is now $212 on amazon. They have several Autel scanners.

Paul