Break peddle goes to the floor
 

HI guys,
Well living in the jungle can be a real pain. here's today's pain.
I live on a hill so I can coast to "the coast" so to speak at least to the main road (path) A N Y W A Y
part of the way down I don't need to brake. but at the same place on the road every time I apply the brakes the peddle goes to the floor. one pump and its back up, good braking power, not soft or spongy.
I have owned blazers since 1986 and do all my own work so I'm not scared of anything (although I do get a little pissed now and then.
Another thing is the the ABS has never worked I've owned this Blazer for 4 years. ANY HELP? Thanks Kim

Start bleeding the brakes from passenger rear,then driver,then passenger front,then driver front. let us know if it helps..


abs sucks on the older models.

If th bleeding don't work its possible something in the drim brakes

How's the fluid in the brake reservoir? If or when you apply the brake and the pedal goes to the floor is the truck on an incline? One thought I am having is if the fluid is getting low and the level of the fluid shifts on a hill it could let air into the master cylinder. That's why there are max and min level marks on the reservoir. What is strange is you say after the pedal goes flat to the floor they work good again. It might be possible the master rear seal is going out and letting pressure to pass. Can you see any signs of fluid under the master cylinder on the outside of the vacuum unit? Even just a tiny trail could cause an intermittent pedal failure.

Thanks for the posts. I don't think I have a leak, I'm not loosing fluid. To be sure I will have to bleed the lines again really well and I'll check around the MC for and trails.

Also, I would like to remove the ABS unit. Has any one done that? 90% of my driving is in 2nd gear on bad dirt roads.

Sometime back mine did something like that, yet at the very bottom they caught, and I had good brakes. The problem was that ABS unit. It has 2 pins on the back side, one of them opened up letting the brake fluid bypass.

At that time I got a used one from a wrecking yard, it worked for about 1 year, them did the same thing that the original one did. I them made me a metal band, fasten it to the nuts at the top and bottom of that pin. Brakes been working great for 2 or more years now.

That may not be your problem, but thought I would mention it. I thought seriously about removing that thing, but this fix seems to have worked pretty good. Here is a picture of it and you can see the metal I bolted onto it to keep the pin from pushing out and letting the fluid bypass.


http://img708.imageshack.us/img708/3...cf0036k.th.jpg

Interesting jerry,

Here's a link to my ABS bleeding. https://blazerforum.com/forum/1st-ge...or-tool-58460/

With the valves depressed like you have it is allowing the high pressure circuit to bypass to the brakes. That's assuming the ABS pump is running. But even without the ABS pump running I am wondering if there is still master cylinder pressure active at the valve and pressurizing the brakes. So if the pedal is weak, and bypassing the valve helps the brakes what could be causing this? Some where in the ABS unit there must be a problem shunting off the master cylinder pressure causing the pedal to travel to the floor, and bypassing the valve allows the pressure to travel pass the problem. I would assume if the ABS light is on then the pump isn't pressurizing the ABS system, so it makes sense without the pump running the brakes would still work.

It's starting to sound more like an ABS problem kim is having. Not sure why it would happen on the same spot of the road each time. Probably at this point pulling the code for the ABS is the best idea, I think kim said the ABS light was on.

With the pin held in it does not bypass, it bypasses when the pin is extended, and without the strap on there the brake pedal goes to the floor for the pin extends out.

With the strap on there I've got solid brakes.

The unit cost about a $1,000 bucks, and the strap cures the problem on mine.

This might help you find the problem Kelsey-Hayes 4WAL Antilock Brakes scroll down to the bottom and read about the RWAL low pedal problem. I know some blazers are 4WAL but this might be the cause of the pedal going to the floor.

I think taking the ABS unit out can be done. Just have to re-route the brake lines to and from the ABS unit back to the combination valve. Not sure how it would impact braking, but it looks like on my blazer combination valve has just one front output and one rear output. Here's what you need to figure out, is the combination valve below the master cylinder a proportioning valve and a tee fitting after the combination valve so you can run both left and right front brakes from the single line. It looks to me since the front and rear brake lines coming the master cylinder are different sizes the combination valve has another purpose sides proportioning. Hopefully someone has done this before and can give you information. I am sure the ABS computer isn't going to like it but if you can stand the ABS light being on who cares.