Brake Pump runs all the time

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Brake Pump runs all the time

August 19, 2010, 12:49:46 AM

Ok so here is a quick rundown of what has happened so far.

Went through the trouble shooting guide and found that I had a bad pressure switch i replaced the switch while I had the motor out. Sometime while either pulling the motor or putting the motor back into the car the rubber line from the resivior came disconnected and emptied the res. Well I wasn't even thinking about the brakes when I was trying to get the motor running. Now that I have the motor running and am trying to get the brakes to work. I replaced the rubber line and filled the res back up now the pump runs all the time when the key is on I have gotten a chance to actually drive the car to see what the brakes are like and they seem to be working correctly. The pump did run several times with the res empty for a few min at a time do you think that I fubard the acspoogeulator? or do I just need to blead the system down.

Brake Pump runs all the time

Reply #1 – August 19, 2010, 01:21:56 AM

I would bleed them first and make sure all the air is out of the system then go from there .
I had to replace the whole unit on my Mark VII and I used almost a whole quart of fluid just bleeding it .
There is an actual procedure to bleeding that uses the pump , but I dont remember exactly how I did it.

Brake Pump runs all the time

Reply #2 – August 19, 2010, 09:14:45 AM

I'm having the same problem.

Brake Pump runs all the time

Reply #3 – August 19, 2010, 09:40:22 AM

I thought your brakes were still hard as hell mine seem to be braking just fine the pump just runs whenever the key is on and stays running untill I turn the key off Im going to bleed the system this weekend and see what I come up with.

Brake Pump runs all the time

Reply #4 – August 19, 2010, 10:53:50 AM

I guess I missed that part of your post, sorry. I will be watching your results though. Good luck!

Brake Pump runs all the time

Reply #5 – August 20, 2010, 01:56:20 PM

If the pump won't shut off, you have either air trapped in the system, a control valve stuck open (sometimes you can see the fluid circulating around the master reservoir), or a fried pump. They don't like to run dry. Did the fluid look metallic at all?

Brake Pump runs all the time

Reply #6 – August 20, 2010, 02:07:48 PM

No fluid didn't look metallic. I am guessing that I have air trapped in the system being the hose from the res to the pump came off and the pump ran with no fluid. If this is the case is there any special way other than following the NATO write up on bleeding the brakes?

Brake Pump runs all the time

Reply #7 – August 21, 2010, 03:06:20 PM

Forgive me, but I am not sure what the "NATO writeup" refers to.

You can use a scan tool to cycle the pump and valves, but most people don't have access to that easily. You can also run it through some ABS cycled hard stops if the abs light is not on and you have enough brakes to force a lockup situation on soft ground like dirt etc. Alternatively, you could try the hillbilly method- pumping down the pedal (assist pressure) with the key off to dump any acspoogeulator pressure, remove the acspoogeulator and turn the key on for a very short time to let it pump fresh fluid out of the fluid passage to the acspoogeulator. The pump can put out an extremely high pressure, but it's not a huge volume so it shouldn't make too big of a big mess; just don't stand over it. Put the acspoogeulator back on and see if the pump builds pressure. You can rinse off brake fluid with plain water when you're done. You might get it burped out enough to get the pump off until you can drive it and do some ABS stops.

Short of cycling the controllers with the scanner I don't know an easy way to bleed it. I think I still have a TEVES brake system guide in my old dealer tech info stash from my Oldsmobile days. I'll see if I can find it in case I'm missing anything.

Brake Pump runs all the time

Reply #8 – August 21, 2010, 03:14:28 PM

http://www.thelincolnmarkviiclub.org/phpBB3/viewtopic.php?f=12&t=463

I dont know what NATO says , but this is how I did my Mark VII

Brake Pump runs all the time

Reply #9 – August 21, 2010, 03:59:09 PM

I think in this case we are looking at an air lock in the pump, like it's lost it's prime, if you will. It will be a lot easier on both your leg, and the pump to burp it at the acspoogeulator passage as it is before the rest of the system. The fluid volume should be about the same as you see at the bleeders.

What you don't want to do is to have to push all that air through the whole system if you don't have to. Once the acspoogeulator passage is bled out then continue with bleeding as hypostang above suggests (FYI, that's a great way to bleed the rear brakes circuit in general- great link!). It should go quickly then.

If nothing comes out of the acspoogeulator passage, then there is an inlet blockage to the pump or it's likely toast.

Brake Pump runs all the time

Reply #10 – August 21, 2010, 04:34:30 PM

When you say burping it at the acspoogeulator passage are you meaning that I pump the brake 30 or so times with key off then remove the acspoogeulator then turn the key on to let the pump flow to the open port where the acspoogeulator was?

Brake Pump runs all the time

Reply #11 – August 21, 2010, 06:32:15 PM

Exactly. Pump the pedal until it is hard as can be- no assist left at all. Do this with the key off (completely out of the ignition cylinder if you want).

Remove the acspoogeulator.

Then turn the key on and let it flush fluid out of the Acspoogeulator hole. This should only take a few seconds, maybe up to 30 I suppose.

Turn the key off and reinstall the acspoogeulator.

Turn the key on and finish bleeding as suggested above if necessary.

Brake Pump runs all the time

Reply #12 – August 21, 2010, 07:25:11 PM

I learned something today , I had no idea you could bleed at the acspoogeulator port .

Now I can't wait to see how you make out :D

Brake Pump runs all the time

Reply #13 – August 21, 2010, 07:36:16 PM

Sorry, I don't mean to hijack but when you run the pump with the acspoogeulator removed fluid should pretty much gush out of the hole where it was right? I was working on replacing my brake system with my spare unit when I decided to try this after reading oljeeptek's posts. The fluid bubbled up and after about 10 seconds overflowed just for a second then receded for a few seconds of stillness before bubbling up again and beginning the cycle over. Did I just possibly find my problem?

Brake Pump runs all the time

Reply #14 – August 22, 2010, 11:18:42 AM

Ok I removed the acspoogeulator let the pump run long enough to turn the key on run to the booster to see if fluid was comming out. Fluid was comming out didn't take long to go through half of the res. Alltho the fluid was not squirting out of the acspoogeulator hole which I really thought that it would be it was more like just a steady overflow. Then I turned the key off reinstalled the acspoogeulator. Still running full time. On to bleeding the brakes maby today if I can talk the wife into pumping the pedal for me.