Brake Bleeding Proceedures

[wohlmeyer]

Hi all,

 

I have a 95 S4S that had a failed master cylinder.  I replaced the master cylinder and when I was bleeding the brakes (using the procedure I found on espritworld.com) I was unable to get the pump to push fluid to the rear brakes.  The pump runs constantly and I followed the procedures for the pump that runs more than 60 seconds.  Still nothing. The pump is getting fluid but doesn't pump the fluid.  I tried to push fluid through the pump with a vacuum pump but still nothing.  Anyone else have this issue?  Pump running but wont pump? 

 

Thanks

 

Bill

[dodge1979]

Bill, I did quite a detailed thread last year on this system and how to get it working correctly....its in this section......delco brakes and how to get them working properly...have a look for it and itll give you all the incite you need!

Darren

http://www.thelotusforums.com/forums/topic/50411-delco-brakes-get-them-working-successfully-and-well/

[wohlmeyer]

dodge1979, thanks for the info.  I read your thread as did my mechanic.  We are well into the system at this point.  The master cyl has been replaced and the system is functioning as it should electronically.  The pump constantly runs but wont pull any brake fluid to the rear of the car.  It sounds like the same issue that Russ91SE posted eariler...  but he never posted a follow up as to what the final solution was...  My mechanic is currently stumped and wants to replace the pump.  I have calls in to JAE and Lotus but still no answer.  Im tempted to have him pull the pump then I was going to take it apart to see if anything could be done.

[dodge1979]

If your getting fluid through the front under pressure (i assume) then it wont be the pump as that will be providing pressure...when you say it runs all the time, is this wen your trying to bleed the rear, or when all bleed nipplesare closed and with ignition on? Ie ignoring the fact the system isnt bled properly, ignition on as if your about to start the car. Does the pump run for forty seconds then cut off or does it run constantly..

Ps im assuming youve satisfactorily bled the fronts?

Oh, and pps, you say the master cylinder was faulty.how did you come to this conclusion and where did the replacement come from? Assuming its a used item, as new are unavailable, its possible that it is a, faulty, b, not from an Esprit (other cars used the system).

[wohlmeyer]

The master cylinder came from Lotus through JAE.  It is brand new.  It cost nearlly $1000 bucks.  The old one was faulty because you could not get the piston to push down even with both feet on the brake and the bleeder screws open.  The new one installed, the piston presses down just fine. 

 

The pump runs constantly when the ignition is turned on.  It never shuts off.  The factory proceedures state to bleed the front brakes first then turn on the ignition to bleed the rear brakes.  So I was not running the pump to bleed the front brakes which bleed fine. 

 

Even though the pump is running, it is not pushing any of the brake fluid to the rear.  I know this because i have changed the color of the brake fluid to blue.  The fluid doesnt move and the pump wont take fluid even if vacuum is applied to the system to force fluid to the pump.  It is like the pump has lost its prime?

 

Does any of that help?

 

Bill 

Dodge1979:  My issue sounds IDENTICAL to this guys issue posted in September:

 

Posted 03 September 2012 - 11:36 AM

The brakes were working OK, but it is time for a fluid change, and the hose from the reservoir to the pump was sweating fluid. Since I put it all back together and bled the fronts, now the pump isn't working properly. It runs non-stop.
Here's what I've done so far:
I removed the old fluid from the reservoir using a Mityvac hand pump, sucking it out of the front and rear chambers. I cleaned out the interior where there was some crud clinging on.

I removed the old hose running from reservoir to pump and replaced it with a translucent hose. This made it easy to see the clean fluid going in when I filled the reservoir.

I have the Delco brakes manual and started the bleeding procedures as described. Fronts went OK, clean fluid coming through. Again I used the Mityvac system at the bleed nipple, rather than the brake pedal pumping method.

At the step where you're supposed to pressurize the accumulator before moving to the rear brakes, the pump never shut off, and because I had the translucent hose I could see that the fluid wasn't moving. The hose was only about half full of fluid, and had air at the pump end. I had the thought that the pump was cavitated and worked the hose to get fluid to the pump input, and tried again, but no good.

I pulled the hose off the pump end, plugged it and sat it off to the side. then I hooked up another translucent hose and hung it vertically down to the pump, filled with fluid and turned the key. No movement on the fluid. I can hear the pump running, but there is no suction. I even hooked up a tire inflator and tried to put some pressure on the fluid. It moved forward, but when I shut it off, it came right back to the same level it started. I tried with the pump off and pump on with the same results.

Apparently the pump isn't moving any fluid, so I'm left with the thought that either the pump has gone bad internally, or there's some blockage downstream from the pump (to, or in, the accumulator?) preventing and fluid movement.

I thought about trying vaccuum pressure (rather than the positive pressure that I tried) on the pump but I'm not sure if that can help or just make it worse. I've also thought of opening the nipples at the rear brakes and trying to get fluid through the system that way. I would appreciate any inputs. It's kind of frustrating because it was working before I started, and I didn't think changing the hose would cause such a problem.

BTW, the translucent hose wasn't brake fluid compatible and started sweating after 4 days, so I switched back to black EPDM. Seemed like a good idea, but didn't work out. It was worth a try and it let me see that the fluid wasn't moving.

Thanks for any thoughts or experience you can share.

Russ
BRG91SE

 

 

I WISH HE WOULDNT KEEP ME IN SUSPENSE!

 

Bill :-) 

[dodge1979]

Ok, ignoring the factory manual procedure for bleeding the brakes for a moment, have you tried bleeding the rears the tradition way? Ie, ignition off, and either a, opening both rear nipples and allowing fluid to gravity bleed over a length of time, b, attaching a vacuum bleeder (not a pressure bleeder like gunsons) and pulling the fluid through? You may need to depress the pedal somewat to assist...alternatively, and I would do this first myself, bleed out of sequence by starting on the master unit itself.attach a vacuum bleeder to the left nipple (so outboard one on the left hand drive), open just enough to get fluid to start moving, then when clear bubble free fluid flows, close and repeat on the right hand nipple(inboard). Right and left as if your sitting in the car. This should prime the master cylinder. Now you might want to put a little grease or something around where the nipple threads into the cylinder body as its possible to easily draw air in through the threads here..happened to me first time round. Once your happy this is bled, the try the rears the old fashioned way with the vacuum bleeder.

If you manage to bleed the cylinder but still struggle with the rears, try skipping them and cycle the abs solenoids as per factory manual...pedal slightly depressed, ignition on for three seconds, youll hear a click, ignition off and do this ten times.

Then, bleed the master again to check as before, then try the rears with the vacuum bleeder again. It sounds very much like there is a vacuum inside the new cylinder holding fluid from moving.

At the end of the day the pump will run continually untill pressure is achieved and if its not getting any fluid itll keep trying. Now yes, the pump can go faulty but thats the last resort. The bleeding method needs to be done out of order firstly in order to just get fluid going, which I found when I first assembled mine...then after a.couple of goes the method I detailed in the post should sort it all out.

On another note, I hope you changed the hose that goes from the master to the pump for new, as these do sweat fluid over time...

If you need to pm me please do so. Give this all a.try and get back to me and we will take it from therr..

Regards, Darren

Ps, not sure what your factory manual states and whether it differentiates between left and right hand drive, but mine says (with regards to master unit bleeding) inboard nipple first then outboard. This is correct, but should be opposite for left hand drive, as when the unit is.moved to the opposite side of the car, my inboard (left hand) becomes your outboard (still left hand) if you get me!

[wohlmeyer]

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 wasn't going to say anything until it was all done but 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.

[wohlmeyer]

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.