Brake Bleeding Proceedures.

[wohlmeyer]

Hi all. IM looking for advice that doesnt involve using a witch doctor or human/animal sacrifice. Im working on my 95 Esprit S4S with ABS and am having trouble with the brake bleeding proceedures. I cannot get any fluid out of the rear brakes. I found bleeding instructions on esprit world and followed them carefully. I have fluid supply to the booster pump but nothing coming out of the pump. The rubber hose from the master cylinder to the pump had some sort of red looking contamination in it. I have even tried using a vacuum pump to help draw fluid through the pump to get it started pumping but it did not help. I have replaced the master cylinder which was likely destroyed by the same contamination. Any advice? :-)

Thanks again!

Bill

[Wmangm]

Do you know what the red contamination is? Tranny fluid? If it is an oil based contamination you are screwed as it will attack all the seals in the system. Is the master cylinder cap seal deformed?

[wohlmeyer]

I have no idea what the contamination is. You are correct in that it really messed up the master cyl. I had to buy a new one. Thinking about pulling the break lines completly off the car and blowing them out with compressed air because right now the fluid will not move.

[Wmangm]

That is bad news. Oil in a brake system pretty much destroys any seal it comes in contact with. The fact you cannot get fluid through to the rear calipers is very bad. I have seen a few cars with this type of contamination before and the only solution has been to replace every piece of rubber in the system with a very thorough flush of the brake system to ensure that it is completely contaminate free. This meant replacing caliper piston seals, master cylinder seals and reservoir, brake hoses and abs unit. The telltale sign of oil contamination is the reservoir cap seal as that is the entry point of the contamination in most cases and the first seal to come in contact with the oil. If your reservoir was destroyed I would be very concerned with the condition of the rest of the seals. I hope this is not the case as it makes for a crumby new year. Last time I saw bad contamination it was on a brand new Cadillac XLR-V, it wasn't pretty.

But look on the plus side, great excuse for brake system upgrades?

[lotus4s]

Have run across this before on 2 other S4s's. Save yourself a lot of grief and replace the lines. It's not worth trying to clean them out. The inside lining of the brake lines is delaminating or at least that was the issue with the ones I dealt with...

[carbuff]

Just to verify,

The rear brakes on the GM ABS cars are only actuated by the pump, which is run via the brake pedal.

To bleed, you need to have the engine running...then press down on the brake pedal. If the lines are OK, you will then have flow to the rear lines.

You can't do this with the engine off...

+++++++++

I bet there are many 90 - 95 Esprits with rear brakes that have NEVER had the fluid replaced...

Not that their owners or mechanics haven't THOUGHT they did it.


(I bet the old brake fluid has contributed to the degraded rear lines)



PS, our friends at JAE sell a nice set of stainless-steel braided brake lines for the Esprit.

[sailorbob]

The ABS pump does not require the engine to be running to provide system pressure but the ignition needs to be on.

[lotusespritse]

He said he carefully followed specific instructions, so I have to imagine he had the ignition.

Could be something else causing the pump not to run.


Sent from my iPhone using AutoGuide.com App

[Wmangm]

Originally Posted by carbuff

Just to verify,

The rear brakes on the GM ABS cars are only actuated by the pump, which is run via the brake pedal.

Umm... No they are not. ABS is a secondary system that is a flow through block unless the system is actively controlling wheel slip. The pump is usually active during the bleed routine to purge air from the ABS unit and to reduce bleed time and improve the bleed of the rear brakes due to the long line length.

[sailorbob]

The pump on the Delco Moraine IIIA system provides power assistance. When the ignition is not on you only have unassisted front braking.

[wohlmeyer]

I should have been more clear on the red junk. It looks like soft flakes of something. maybe a inner liner of the line from the brake fluid reservoir to the pump?
It does not show evidence of petroleum contamination. No swollen cap or other rubber parts so I don't think that is the issue. If I am reading and understanding the directions correctly the front brakes are fed directly so they will bleed without the pump running however the pump must run and must build some pressure before the rear brakes will work or bleed.
The pump is running and in fact never shuts off so I followed the directions for the pump running for more than 60 seconds in the bleeding instructions but that did not help
I will play with is some more but it is like the pump has lost its prime?
the pump runs but has no suction or pressure. I also should mention that I made sure that there is fluid going into the pump. I think I will replace the pump inlet rubber hose tomorrow just in case the red stuff is coming from that hose.

[jtrealty]

The tiny passages and ports in the ABS system may be plugged up with the red stuff. You might try reverse pressure bleeding to push the stuff back out instead of trying to force it through. Before replacing the brake lines I would confirm they are plugged up. Although it is possible to bleed the Delco system manually, the best way to do it is with a Tech 1 if you can get one.
David Teitelbaum

[wohlmeyer]

I replaced the inlet hose to the pump and made sure again that there is good fluid supply from the master cylinder.
I tried forcing fluid under 2-3 lbs pressure into the inlet while the pump was running to see if it would start pumping- no change.
I think the next step will be to remove the pump assembly from the car and take it apart to see if anything can be done. I am not excited about this because most pumps of this kind were not made to be serviced.
I have read about the switch problems but it appears that those would keep the pump from running and it is running fine.

Unless someone has a better idea I guess replacing that pump is the next logical step.

Bill

[wohlmeyer]

Have any of you ever used this program to diagnose brake system problems?

Lotus Esprit S4, British Racing Green


Bill

[sailorbob]

Espritmon is a good, useful program.

I do not think it will help with your problem though, I suspect you'll need to go through the ‘Hydraulic Diagnosis’ fault finding procedures.

[sailorbob]

Have you tried bleeding the pump in case it's air locked? De-pressurise the accumulator (important!) and crack open the high pressure line from the pump assembly. You should get brake fluid within a few seconds.

[wohlmeyer]

unfortunately that line is bone dry with or without the pump running. I tried a vacuum pump on the high pressure line with the pump running but no help.

gonna pull the pump and bench it, take it apart and see if anything can be done.

[wohlmeyer]

follow up: Update:


Removed the pump and dismantled it enough to know that I can't repair it. I have found a company that was reccomended on one of the Ford forums for the cars that have a integral abs system. They quoted me 395.00 plus shipping to rebuild the pump.

After having the pump partially dismantled I am even more sure that nothing in the bleeding procedure will make the pump start pumping. The fluid comes from the reservoir to the inlet of the pump under gravity pressure and goes out of the pump into the master. there is a one way check valve that prevents fluid flow from the master into the pump. fluid can only go from the pump to the master.

im sending the pump in to be rebuilt today.

[wohlmeyer]

I got the pump back yesterday and installed it last night. Turned the key on and it immediately pumped fluid. I am hoping I can get them bled tonight but if not then it will be on sunday. I will let you know.
I was very excited when it pumped.

This is the business that did the rebuild:

S.I.A. Electronics
730 North Minnie Street
Tilden, IL 62292
618-587-3308 800-737-0915

I found their name on a website of a Ford and Lincoln owners group that said they had had good luck with them. A lot of the early 90's domestic products used a integral ABS system that is similar in operation to this system.