I have a 1994 xjs with 111k which has been a daily driver. The brakes are hitting the floor and I want to try to flush out the system. I do not think it has ever been done. Is this a diy job? Any input is appreciated.

 

I certainly hope it's a DIY job since I'm going to tackle it soon

Since you have a 1994 like me I'm assuming you have the Treves MKIII ABS system. The fronts bleed normally (I'm planning on using a Motive power for them). The backs are a bit different. With the ignition 'on' you bleed by holding the brakes in for no longer than 2 minutes (until they run clear).

Hope that helps.

 

I assume you mean the brake pedal is hitting the floor - this is not good and I would get it fixed ASAP you don't want to run out of brakes.

Firstly check the fluid reservoir is it leaking fluid?

A long pedal usually has 2 causes
1. Air in the system
2. Leak in the system

Air is compressable unlike liquid and when you press the pedal the air compresses and allows the pedal to travel further. Bleeding the system of air will solve this.

Leak - this is more serious as you will eventually run out of brakes. If you have a leak you will need to identify where it is leaking.

Just flushing the system will not fix the problem if it is a leak. Identify the cause first and fix it. Then flush and refill.

cheers WJ

 

Yes makes sense having to keep the ignition on.

I just hit the brakes real hard a few times and it seemed to tighten the brakes up. Occassionally I would get a low pedal but the brake light miraculously stopped coming on after I hit the brakes hard, almost skiding. Not sure whats going on but I'm guessing air in the lines as opposed to a leak so I'm just going to replace the fluid and bleed them.

Thanks for the help. I'll keep the result posted for others.

 

As long as you're going to be going over the brake system, check for the leaks and see how your hoses are looking. If you don't find any, bleed and then pay close attention to the level for a bit to make sure you didn't miss a leak.

BTW, what colour is your fluid - almost clear or molases? That would be a good indication of how long it's been in there/ how much water is in it.

 

When looking for leaks don't overlook the caliper pistons. I'm not sure about your year but my 1990 had chrome plated pistons that were rusting and causing leaks. It is also important to bleed them in the correct order. I believe it is right rear, left rear, right front, then left front.

Good luck!
Dan
1990 XJS V12 convertible Marelli

 

After more research on this I have determined that it is the brake accumulator. They commonly go bad.

It was a clicking sound on the right side of the dash that lead me to this. Also, the brake llight coming on when the brakes are hit hard. I ordered an AC Delco 25528382 accumulator which hopefully works. Others have used this on Jags with success. It only cost 120 as opposed to 500 for the jaguar part.

I looked into bleeding the brakes. the manual says bleeding sequence is right rear, left rear, right front and left front. If I just bleed from the left front, could I just press the brake until new fluid comes out. Wouldn't that bleed/ flush the whole system? I'm new at this...

 

Brake Accumulator question. As I did extensive searching on an acumulator, I noticed they all kind of look the same, and most are manufactured in Germany... Does anyone know in detail how the system works. I'm guessing there is a standard pressure with these things of about 1500psi. If there is a standard, as long as the thing fits it should work fine? If this is the case, one could just get a bmw accumulator (if the threads are correct) for close to $100. I'm guessing the chances are better that you would get a newly manufactered accumulator from bmw since there are so many bmers on the road.

The AC Delco part I ordered is said to be old stock on one of the Amazon reviews. It could be 20 years old, meaning it will just go bad again soon...

Any Accumulator experts out there?

 

Can't help you with the accumulator question. I have read that some GM (specifically Cadillac) accumulators will work but any further and I haven't seen.

As for the just bleeding one caliper, that would work fine if the brake system quickly moved the fluid around. However, it is a system with four arms/ends and the 'gunk' tends to stay in those end points. To do it right, you need to clear all four of those arms by bleeding each wheel.

 

I put the accumulator on today. All the reservoir fluid drained out in the process (I left the old one off over night...). I just filled it back up with fluid and the brakes have been working great. No more brake light or abs light coming on when I brake. There is some air that I will need to bleed out because I accidently let the res go empty, but nothing too dramatic.

btw, the old accumulator came right off with PB Blaster.

I used the AC Delco 1990 Buick Reatta Accumulator. The part number is listed above. It cost $120.

 

I was over at the new house today and dug my book out the correct bleed procedure for a LHD car is
FR FL RR then LR

 

Seems like a good place to throw out my plan to see how daft I might be. I have a Motive Power Bleeder (a pressurized tank that feeds brake fluid into the system). I was going to use it at pressure to do the fronts as you would any car and use it at lower pressure (just to keep the fluid going into the system) and do my Treves III system as directed in the back holding the pedal. Would this work?

 

Are you sure? front before rear? I'm just not buying it... hehe

 

Hi Guys, I'm fairly new at responding to this Forum. so here's my situation about the brakes on my 89 XJS. I replaced the front wheel bearings, and separated the brake calipers to remove the rotors. After installing the rotors and resetting the brake calipers, I attempted to bleed the RF brake caliper. I put one end of a tight fitting tube on to the bleeder nipple and the other end into a clear plastic bottle. I submerged the tube in some clean brake fluid. Then I loosened the bleedervalve and proceeded to pump the brake pedal. The brake pedal went to the floor. I tried pumping the brake pedal many times, but without success. The master cylinder reservoir is full. but there is no fluid flow. There is no back pressure on the pedal. Any suggestions??

 

Did you have someone tighten the bleed nipple while you held your foot to the floor on the pedal and then loosen after you released the pedal?

Does your car have ABS and do you have a ROM?

Forgot to ask did you drain the system of fluid?

 

The car does have ABS. There is fluid in the reservoir. Both front calipers are completely drained. Pedal goes to the floor when bleeder nipple is closed also when open but connected though a tube to a bottle partially filled with brake fluid; tube end is submerged below the fluid level.

 

I'll assume your accumulator is fully charged with fluid and you have a LHD car.


Just a quick overview of the process:

Bleeding the brakes is like a pump.
Pushing the pedal increases the pressure in the system, fluid can not flow back into the reservoir so when you open the bleed nipple fluid will flow into your bottle. As the pedal is released the system will suck fluid or air back into the system if the bleed nipple is not closed.

The procedure to bleed the brakes is as follows;
1. Ensure the reservoir is filled to 2mm below the filler neck.
2. Connect the bottle and tube as you did before starting with the RH front (LH front if RHD car)
3. Have someone push on the brake pedal then open the bleed nipple SLOWLY or you might wear brake fluid. DO NOT push the pedal to the floor all that is needed is enough pressure to move the pedal.
4. Tighten the nipple before the brake pedal is released. Then release the pedal.
5. Continue this process until all of the air is purged.

Repeat the process on the other side and then rear. Regularly check the reservoir to ensure there enough fluid you don’t want to suck air from the reservoir.

It is very important NOT to pump the pedal with the bleed nipple open this will just suck air or fluid from the bottle.

IMPORTANT NOTE: adding fluid to the bottle and keeping the tube in the fluid will prevent air being sucked back into the lines if your helper releases the pedal before you tighten the bleed nipple

Hope this helps WJ

 

I am not sure where to find the accumulator for ABS brakes. Is that different from the reservoir on top of the master cylinder?

It is a left hand drive so the RF brake is first to be bled.

I do understand the procedure you outlined. However, there is no back pressure on the brake pedal at all when the bleeder valves are closed. The fluid level in the reservoir does not decrease.

 

The accumulator will be on the RH side where the master cylinder would be on a RHD car.

Make sure the car is level with the ignition off pump the brake pedal at least 20 times the pedal should become hard.
Turn the ignition on you should hear the ABS pump run for a short time it should turn off in less than 60sec.

Does this happen?

 

The accumulator pump starts and runs for some time and then stops. I tried pumping the pedal after the accumulator was filled. Still no hard pedal. I will try again. The car is level. Will report back in 10 minutes.