I have a 93 jag xj6 inline 6 automatic some people call it a xj40 for some reason. Its a cool ride

When I push on my brake pedal the red brake light comes on and the yellow ABS light comes on and I can hear the abs pump running. As soon as I let off both lights go out. Dose this sound like I need to bleed the brakes or something different

Also when I drive my jag from about 5mph to 25mpg I can feel the hole car do like a hoping motion up and down. Anyone have ever experienced this before?

 

Hi jagking93, if you go to the link below and repost your question there you will get help from people with the same model.

XJ40 - Jaguar Forums - Jaguar Enthusiasts Forum

 

Any DIY gurus about to offer some help for a newbie?

 

Hi jagking93,

Welcome to the Jaguar Forums!

XJ40 is the Jaguar factory code for the XJ saloons (sedans) manufactured between 1987 and 1994. Your '93 is equipped with a hydraulic brake power boost system that stores pressurized fluid in an "accumulator," the metal sphere mounted on the right side of the firewall in the engine compartment. The accumulator threads onto the valve body to which the electric pump motor and a combination low-pressure/warning-lamp switch are also attached.

The accumulator contains two chambers separated by a diaphragm. On one side of the diaphragm is pressurized nitrogen gas. The electric pump fills the other chamber with hydraulic (brake) fluid, and as the diaphragm moves, it compresses the nitrogen in the other chamber. The result is that a charge of highly-pressurized fluid is stored in the accumulator. It is this stored pressure acting in the boost solenoid that provides the power assist for braking.

When the accumulator loses its ability to store pressure (usually due to failure of the internal diaphragm), the only pressure in the system is what the pump can develop in the network of brake lines. As soon as you depress the brake pedal, that pressure dissipates and the low-pressure/warning-lamp switch illuminates the warning lamp on the dash and starts the electric pump motor to recharge the system.

You can test your accumulator by the following procedure. Do not run the engine above 2000 RPM for more than 30 seconds though:

"Check Accumulator :
Run car at 2000+ RPM for 30 seconds. Shut motor off and turn key to Position II to activate VCM. Pump brake pedal slowly, 3 count intervals, check the number of times before the low brake pressure warning light comes on (the brake pedal will become hard). A fully charged accumulator will go 9 pumps. 4 pumps indicates a need to service the system, probable accumulator diaphragm failure."


For more information, search this forum, and also the XJ40 archives and eBook at the Jag-Lovers forum, which are full of information about the Teves brake system. Note that there is a more affordable GM/AC Delco accumulator that will fit some XJ40s, but I think I recall that it will not fit our late XJ40s.

Hopefully one of our resident experts will chime in and correct any errors in the above.


Cheers,

Don

 

is this what the item you are talking about looks like? I did the test and it failed so I am looking to replace the part. Before I go spend big money I need to make sure we are talking about the same part

 

Hi jagking93,

The large black metal sphere is the hydraulic brake accumulator. The black cylinder with the electrical harness is the pump motor. The silver cylinder with blue electrical connector is the combination low-pressure/warning-lamp switch.

If you shop around and do some homework, you may be able to find a more affordable price on the accumulator. According to reports in the Jag-Lovers XJ40 forum, ACDelco part number 25528382 as fitted to several GM models from 1986-1990 is identical to the Jaguar accumulator. At the time of those reports, prices on the ACDelco part were as low as $115.00, but I'm sure that if still available the price has probably increased.

Here's a link to the GM vehicles that used the ACDelco 25528382 accumulator:

http://parts-catalog.acdelco.com/cat...&parttype=4106


This link indicates that the Chrysler TC "by Maserati" also used this accumulator, but that info is not likely to help us much, given the rarity of those cars:

http://forums.aaca.org/f144/tc-brake...rt-372234.html


I suspect that the accumulator used on some BMW models from that period may also be the same, but I have never confirmed it. Has anyone else?

You might also check eBay for a good salvaged accumulator which might get you down the road for awhile if the price is right, but spending too much on a used accumulator might prove to be a false economy if it fails sooner rather than later, especially since eBay sellers seem to want a lot of money even for used accumulators. One benefit of purchasing a salvaged assembly like the one in the photo you clipped from eBay is that you get an extra motor and switch, both of which are no longer available new and can be very expensive even when used.

Please keep us informed.

Cheers,

Don

 

I went out and looked at my jaguar. On my accumulator I have a very large warning sign on it that said do not remove under extreme pressure! What is the correct way to remove it and install the new part?

 

jagking93

De-pressurizing the system will be easy in your case because your accumulator isn't storing any pressure. With the engine off, press and release the brake pedal about 20 times. I don't think you even need the key in the ignition, but having the key in Position II will allow you to observe the warning lamps coming on as the pressure falls below the threshold.

To remove the accumulator, try an oil filter wrench or rubber-strap wrench to rotate the sphere counter-clockwise (anti-clockwise), but be careful not to damage the mounting points for the valve body or to bend the hydraulic pipes that are attached. If you can't get the accumulator loose without the valve body moving, the only option I've found is to remove the entire assembly from the car, mount it in a bench vise with pieces of wood to pad the vise jaws, then use the oil filter wrench to remove the accumulator.

Be very careful not to damage the electric pump motor or the combination low-pressure/warning-lamp switch.

When you install the new accumulator, you don't need to tighten it much. It is sealed by an O-ring and the fine threads help prevent it from vibrating loose. Install it hand-tight, then use your oil filter wrench to give it a good "snugging."

Cheers,

Don

 

Welcome to the forum jagking93,

When you've fixed the accumulator and get a minute, please follow this link New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum to the New Member Area - Intro a MUST forum and post some info about yourself and your vehicle for all members to see. In return you'll get a proper welcome and some useful advice about posting to the forum.

Graham

 

I had just gotten in contact with the original owner of my jaguar and he told me he had repaired the drivers rear abs sensor. Could this problem caused by a broken abs sensor and not a brake accumulator? I wanted to ask before I spend a hole bunch of $ on a brake accumulator. They seem expensive and hard to come by.

 

Hi jagking93,

If you followed the procedure for testing the accumulator and the test indicated the accumulator is not holding pressure, then unfortunately you probably need a new accumulator. A major clue is that the ABS pump runs when you press the brake pedal. That would not be caused by an ABS wheel speed sensor.

That doesn't mean you don't have a problem with a wheel speed sensor, though. I can't remember if that will trigger a fault message on the dash, but it might be worth turning your key to Position II (ignition ON but engine not started), then press the VCM (Vehicle Condition Monitor) button on the trip computer to the right of the steering wheel. Watch the small display window at the bottom center of the dash for a Diagnostic Fault Code (DTC), which may just read FAIL.

If you see a code that begins with FF with a two-digit number, such as FF68, make a note of it, then, with the key still in Position II, pull the Instrument Cluster fuse in the center fuse box. I think it's the second closest fuse to the driver seat (and maybe Fuse 9 on the fuse chart). With the fuse pulled, watch for the speedometer and tachometer needles to drop a little below 0. Wait a few seconds, then plug the fuse back in. Turn the key to the OFF position. Now repeat - turn the key to Position II and press VCM to watch for another code. Only one code is displayed at a time, and this method of reading DTCs allows you to view and clear them one at a time. Please report all DTCs you may find to us and we'll go from there.

Cheers,

Don

 

I have done the above procedure and I have NO codes showing in Vehicle Condition Monitor window its just blank. I have attempted pushing the button as well with no results

 

That's good. I still think you need a new accumulator. The good news is that accumulators tend to last many years.

Once you've installed the new accumulator, let us know how your brakes work and if there are still any issues.

Cheers,

Don

 

Sounds a bit like mine. Driving home last week suddenly no brakes- or there was if I really stood on them. Brake light and ABS lights on with VCM showing 'FAIL' Managed to drive home with changing gears and pulling handbrake.
Checked the fuses and all OK. Noticed no sound from any pump so wondering if its the pump, pressure switch or the accumulator.
As mine is the '93 3.2l model, there isn't the same pump as the earlier models.
Steve

 

I managed to find a replacement unit at a local wrecking yard and they only want 35 bucks for it.

Before I jump on the deal its from a 96 jx6 I am wondering what year jag's this part will interchanged with my 93 also are the xj6 and xjs the same?

 

There's a site where you can check this stuff - go there and look at the part numbers for each model year and if they match (a lot do, but not all, obviously) you can use the alternate year's part.

here you go:

Jaguar XJ6 and XJ12 parts | Jaguar Heritage Parts UK

use your VIN to go to the appropriate section.

Larry

 

I have replaced the bake accumulator at great financial cost. Then I bleed all of the brake line's. I am still having this same problem. As soon as I push the brake pedal the RED brake light and the ABS LIGHT both come on and as soon as I let up on the brakes they go out.

What the heck am I missing?

I bleed the brakes with the key on engine off. After I first replaced the accumulator the pump ran for about 1 min then it shut off. The pump runs randomly about every 1-3 min with the key on and engine off and then it shuts off.

 

bump^

 

Can you still hear the electric brake fluid pump run when you press the brake pedal? If so, does it shut off on its own, or only when you let go of the brake pedal?

One possibility is that the combined low pressure/warning switch has failed on the low pressure sensing side, in which case it ceases to power the pump when the fluid pressure falls below the threshold.

The Power Hydraulic Manual at the link below may be helpful in diagnosing the cause of your issue:

http://www.jagrepair.com/images/Elec...tems%20S73.pdf

Please keep us informed.

Cheers,

Don