Only One Rear Bleed Nipple?

[simon291971449]

Hi folks

Just completed front-end rebuild, including brakes. Have refilled brake reservoir and need to bleed the rear brakes first.

Got the car up on stands at the back and when I looked I could only find a bleed nipple on the left-hand (ns) caliper. The equivalent place on the RH caliper appears to be where the brake pipe enters the caliper. Then there appear to be connecting pipes which extend across to the LH caliper where the bleed nipple is.

I did read in a post about bleeding the TEVES system that there may only be one nipple, depending on the car. This is a '91 facelift 4.0 with inboard brakes.

Have I got this right, and once the pump has pressurised the system, will opening the single nipple bleed both rear calipers?

Any other advice about the whole bleeding ( ) procedure gladly accepted!

Many thanks

Simon

[ptjs1]

Simon,

The Teves system on the inboard rear up to VIN 188104 uses a cross-link pipe between the calipers as you've described.

You must bleed these Teves brakes correctly. I'll post the Teves procedure later today when I'm back at home. I'd strongly suggest you use their procedure rather than the original Jaguar-documented procedure.

However, if you've disturbed the brake system and reservoir at all, you must bleed the Low-pressure side of the system first before touching the wheel circuits. Again. I'll post the low-pressure bleed procedure tonight.

Cheers

Paul

[simon291971449]

Cheers Paul

That's enormously appreciated. I've read one of your posts about doing it the TEVES way, but the low pressure side is news to me, so look forward to your post very much.

Thanks

Simon

[ptjs1]

Simon,

The reservoir feeds two aspects of the ABS system. It provides the fluid into the actuator unit that is mounted below it. However, it also has a feed to the accumulator and pump which is on the other side of the engine bay. The fluid is then pumped back under pressure to the actuator unit.

If there is ANY chance that air has entered the system, then you MUST bleed the Low-pressure side of the system before addressing the wheel circuits, otherwise you'll be chasing your tail trying to get an air-free system.

To bleed the low pressure side, start by getting lots of absorbent rags and a container such as a plastic or foil take-away food dish.

Look for the pipe that comes from under the reservoir, crosses over to the other side of the engine bay, joins to a flexi-pipe and then joins to a plastic elbow pipe that enters the ABS pump. There is a metal clip pin securing the plastic elbow to the pump. Put the rags and container under the pipe. Remove the metal clip. Then try and carefully wiggle the pipe off from the pump. It can be very stiff so go easy and, don't break the elbow. Look out for the rubber O-ring on the end which should ideally be replaced, but isn't available separately from Jaguar at the moment, but worth giving them a ring as unusually, it is not available but has a price listed?

Fluid should immediately flow from the pipe. Ensure the reservoir is filled and let the fluid flow until you are sure there are no air bubbles, then refit it to the pump body whilst the fluid is flowing. Reinsert the metal clip, Job done!

If you're not sure what you're looking for, see 12.13.14 on the diagram referenced here:

https://parts.jaguarlandroverclassic.co ... nd/jaguar/

You can now bleed the wheel circuits.

Make sure the reservoir is topped up and kept topped up as you'll be bleeding both rear calipers together as your car has the x-over pipe circuit for the rear calipers.

TURN ON IGNITION AND WAIT UNTIL BOTH ABS AND LOW PRESSURE LIGHTS HAVE EXTINGUISHED AND ALSO THE MOTOR PUMP HAS CUT OUT.

THEN, OPEN REAR NIPPLE AND HOLD BRAKE PEDAL DOWN, WITH IGNITION ON FOR 15 SECONDS – NO MORE

TIGHTEN BLEED NIPPLE, TURN OFF IGNITION, RELEASE BRAKE PEDAL.

WAIT ONE MINUTE AND REPEAT FROM RESTORING SYSTEM PRESSURE AS ABOVE.

THEN WAIT ONE MINUTE AT LEAST BEFORE MOVING TO FRONT BRAKES – THIS PREVENTS THE MOTOR PUMP FROM OVERHEATING.

AT THE FRONT, ENSURE SYSTEM PRESSURE IS CREATED AND THEN BLEED CALIPERS CONVENTIONALLY WITH IGNITION ON, USING SLOW STROKES AND GO THE FULL TRAVEL BUT DO NOT FORCE.

ONCE THE LEFT SIDE HAS BEEN DONE, AGAIN WAIT ONE MINUTE AND THEN RESTORE SYSTEM PRESSURE, BEFORE REPEATING FOR THE RIGHT SIDE.


This procedure means that the pump drives the fluid and any air when you bleed the rear circuit.

It also means that the pumped fluid ensures you have boost pressure providing 4:1 assistance acting on the master cylinder circuit when you bleed the front brakes.

Hope that helps. Any probs, do get back to us.

Good luck

Paul

[simon291971449]

Hi Paul

Brilliant! Thanks for taking the time to post all this. I'll have a go at finding a new o ring, and then get stuck in. I'll let you know how I get on.

Best wishes

Simon