1987 ABS question

[RavenVette]

I have an '87 coupe and the left front caliper output of the ABS modulator pump is barely allowing any fluid to come out.
I assume it is a bad solenoid on left front output.
My question, since it is almost impossible to find a pump. Can you remove the input line coming from the MC and
put it in a proportioning type block, feeding the left and right caliper output lines. Thus bypassing the ABS pump, then plug the three ports on the ABS pump, leaving
the rear ABS portion intact. Sorry if this sounds confusing, but it would be quite a simple procedure if it would work.

Any input would be appreciated....Go Ravens

 

[Hib Halverson]

DO NOT, under any circumstances, do a hack job like that on an ABS. The ABS, front or rear, cannot function without the pump.

Trying to jury-rig your way around failure of the EBCM risks loss of control of the vehicle during braking. The result of that could be injury or death.

Your choices are find a rebuilder which can redo your EBCM or remove the ABS all together.

 

[RavenVette]

DO NOT, under any circumstances, do a hack job like that on an ABS. The ABS, front or rear, cannot function without the pump.

Trying to jury-rig your way around failure of the EBCM risks loss of control of the vehicle during braking. The result of that could be injury or death.

Your choices are find a rebuilder which can redo your EBCM or remove the ABS all together.

Hib, thanks for the reply, the EBCM is not the issue, or even with battery disconnected, does the modulator pump control fluid flow? Does a non-working pump do anything other than pass fluid? The proportioning of brake pressure to each caliper is controlled by the MC, is it not, for a non-functioning ABS system? In my situation, removing the ABS would mean bypassing the pump for both front and rear, and pulling the fuse for ABS? I assume you know, you cannot rebuild a Bosch II pump from what I've been told. The issue I am having is minimal fluid to the left caliper, I have checked the line from pump to left front caliper, it is clean.
I had no problem bleeding right caliper which means that right control solenoid in pump is ok, and input feed to pump from MC is ok. With left caliper bleed, brake pedal is almost impossible to push down, but starting car allows it to be depressed a little easier of course, but you can tell the feel is not right. Left caliper/hose is not the issue, as I have checked fluid flow at frame connection before rubber line. Anything you can think of to check I have not checked, or any ideas short of spending $700 on a pump that may or may not work?

Thanks, Bob

 

[RavenVette]

Just to close this out, I found an ABS pump in Colorado for $250 that corrected the problem.
Problem was the ABS pump solenoid output for the left front caliper.

Thanks

 

[Hib Halverson]

Glad you found a rebuilt.

To answer your question about the pump. it's needed to replenish the master cylinder during an ABS incident. Without it, the master cylinder piston would bottom and then...no brakes.