2000 blazer / jimmy brake bleeding issue

[rmwilson]

Its a 2000 ENVOY - build on blazer/jimmy platform: (not sure if it has any special systems as a result)

I replaced (spliced) a section of brake line that had rotted out left rear wheel. (symptom was brake light came on, brakes would feel soft and ABS would kick in at the very last few feet of a stop - started to bleed brakes and saw fluid pouring out rear line) -

The pedal is very soft, no pressure and it won't bleed no fluid coming out of left rear caliper where i worked. Wondering if I have air in the abs system - Brake pressure modulator valve? (Bleed EHCU/BPMV module) - do I absolutely need a scanner to open any closed valves? Are there any hand held personal scanners from automotive stores I can buy that will cycle abs unit (solenoids) any manual way of doing it - i.e disconnect battery, pull fuses, turn key on and off and do a dance????? ?

Any tips or advice on how to get air out of system?

Ryan

[Airjer_]

Is the bleeder clear of any obstructions? Did you take the bleeder all the way out and make sure fluid can flow through it? Di you have somebody pushing down on the brake pedal when you opened the bleeder?

[rmwilson]

Brake fluid was at one time coming out, and then it stopped- I was using a vaccum bllder plus pushing the pedal. I did have a person pressing and holding the brake pedal it was not getting any better worse in fact - ( maybe it was sucking air in from my connection, then it just would not bleed out... I did take the bleed screw right out .. and no fluid was coming out ... I do believe i have a lot of air in the system.

[Airjer_]

Is there fluid coming out of the right rear?

[MT-2500]

Originally Posted by rmwilson

Its a 2000 ENVOY - build on blazer/jimmy platform: (not sure if it has any special systems as a result)

I replaced (spliced) a section of brake line that had rotted out left rear wheel. (symptom was brake light came on, brakes would feel soft and ABS would kick in at the very last few feet of a stop - started to bleed brakes and saw fluid pouring out rear line) -

The pedal is very soft, no pressure and it won't bleed no fluid coming out of left rear caliper where i worked. Wondering if I have air in the abs system - Brake pressure modulator valve? (Bleed EHCU/BPMV module) - do I absolutely need a scanner to open any closed valves? Are there any hand held personal scanners from automotive stores I can buy that will cycle abs unit (solenoids) any manual way of doing it - i.e disconnect battery, pull fuses, turn key on and off and do a dance????? ?

Any tips or advice on how to get air out of system?

Ryan

Make sure you have all lines fixed good.
First step on bleeding is to beed the lines out of master cylinder.
Always wait 30 seconds when you let up on brake pedal.

Start at right rear wheel.
If fluid fails to come out either rear wheel.
Go to combination valve and make sure it is not tripped.
If tripped some times you can open the wheel on front or other line on other side and get the valve to center.
They make holders for combination valve to keep them from tripping and shutting off a wheel.

When bleeding calipers tap side some to help traped ait get out.
The good book says you need a abs capable scanner to bleed the abs part of brakes.
But.
Some times on ABS brakes you can turn key on to help bleed abs unit.

Good ABS scanners with the built in brake bleed are not cheap.
Some are from 3 - 5 grand $$$$$$$$.

[Airjer_]

I've never had to bleed an ABS system after repairing a brake line. The only way I could see air getting into the ABS is if you ran the system empty and then locked up the brakes which activated the ABS. With a fluid leak and a seriously impaired braking system it would be almost impossible to do.

[rmwilson]

I have not checked right rear - the earliest I can check is Saturday as I'll go back and try and bleed them again then.

[rmwilson]

just to follow up and close the post ...

turns out the left rear bleader had no hole in it at all ... a defect maybe.... just seems odd... any way replaced that bleeder and bled brakes after replacing line (using a splice and reflaring the tube) and they work now... still have a very slight ABS shutter when i brake at very low speed... ( 1-2 mph)- the inital problem i set out to fix- before the brake line blew and squirted fluid every where ( while bleeding it) . but i think its my wheel hub bearing and abs assembly acting up.. I'll probably just unplug that sensor and be done with that rather than replacing the $500 wheel bearings!

[Airjer_]

Overactive ABS during a slow stop is usually a sign of a wheel speed sensor dropping out. I have had tremendous luck following the TSB on this problem for GM's. Basically they want you to pull the front sensors, clean rust build up from the mounting area, apply di-electric to the area and reinstall the sensor.

The sensors on the front are held in with an allen head bolt I think. If the bolts break free your halfway there. Gently work out the sensor and your home free. It won't cost you anything to give it a try. It is a lot easier to narrow down the sensor with a scan tool. Cleaning the fronts would be a good start.

[rmwilson]

REALLY ... a GM repair that might not cost me anything is that even possible.. LOL
Where do these sensors sit... what do they look like? do you have any pictures or diagrams where i can see them (I'm a back yard mechanic - no computer - just tinker with my truck ... ( 33 year old male so do not have a a life time of experience with mechanics..)

[Airjer_]

Remove the wheel, caliper, and rotor. You will see the speed sensor bolted to the wheel bearing.

[rmwilson]

I have not had a chance to do this yet .. the dang snow came faster than I wanted... looks like others are having this problem as well from what I can see on newer posts.. I'll have to give it a shot .. sooner or later...