S10 ABS and brake issue

Hello guys, having a problem with my 91 S-10 Blazer 4WD brakes.

The pedal started going to the floor when trying to stop. I have replaced the master cylider, and brake booster. I bench blead my master cylinder prior to installation. I have also replaced both rear wheel brake cylinders.

The pedal still goes to the floor. I blead the brakes but it appears I am not getting any presure build up. Fluid comes out all of the all brakes when bleeding.

I attempted to pruge the ABS unit but I get no fluid out of the top 2 bleeder values. I cracked the drain plug on the left side and get fluid from there, however I never get fluid out of the right side drain plug.

What is the ABS unit called? You think this unit could be bad and give me the symptoms I am having?

The ABS light is also on.

Any help would be greatly appreciated.

Troy

I sure need some HELP here.

I have replaced the master cylinder, brake booster, combination value, ABS Unit, and rear brake cylinders.

I can not get the back brakes to bleed.

I did some research on the net and I noticed it mays mention to 91 and 92 only S10 you have to press the button on the combination valve to bleed the back brakes.

I can not get this to work. When I push the button and press the pedel it pushes it back out.

Could someone PLEASE help me. I have spent more on this repair than the S10 is worth.

The ABS light is now off.

Thank You

Rear wheel or 4 wheel ABS brakes?

Not sure, all of the lines from the combination value are connected to the ABS unit, so that might make it 4wd ABS. Not real sure how to tell unless that is it.

Troy

The 4 wheel ABS brakes will have a speed sensor on each wheel and 4 lines from each wheel runing into the abs unit.
How many brake lines does the abs brake unit have running into it?

5 line, so I guess this would be a 2 wheel ABS

I really appreciate you helping me out!

Troy

5 brake lines may be 4 ABS wheel brakes.
Have tou got front wheel speed sensors?
Check you PM. and let us know if it matches your brake system.

Yes that is the ABS unit I have.

Yes I have front wheel speed sensors.

I have never been able to get any thing out of the top bleeder valves on the ABS unit. Either unit.

So from reading what was PM to me I can now properly bleed the ABS unit. What is a Combination Valve Depressors (J-39177) look like and can I use something other than the Combination Valve Depressors?


Thanks

Troy

Ok you have 4 wheel ABS brakes then.
Follow the bleeding procedure as outlined in the pdf.
They are Kent Moore or gm tools actually valve holders.
Go to Kent Moore tool web site for a picture.
Check with your local parts place they may have some in after market ones.
Or if you have a automotive tool truck like snap on or mac tools they should have something.
Good luck.
MT

thanks It will take me a few days but I will get it done this weekend and let you know.

Thanks again for ALL of your help!

Troy

any chance of posting that pdf one more time, I deleted it by mistake after I printed it out. I need to send it to my son who is working on the truck.

Sorry :banghead:

OK, I am able to get fluid out of the top right bleeder valve now.

I am still unable to get any fluid out of the left (ds) top bleeder valve.

Any suggestions why this might be? As stated before the master cyclinder is new.

Troy

Do you have both of the valve depresser tools installed on it.
Is the internal bleed screw closed?
Also you might try it with key on.
Will try to send PDF again.

I FINIALLY got it, turns to be the (NEW) master cylinder I bought. Went and got another and now it works better than it has in a long time :grinyes: .

Thank You VERY much for your assistance. You have a great website and very experienced staff!

Thank you once again.

Troy

You are welcome.
And thanks for posting back with the fix and how it went.
Bad new parts are a bite. Glad all is well on it now.
MT