I replaced the master cylinder seal and now I cannot get the air out of the brakes. Tried everything, slow pump, fast pump, but to no avail. It seems air is being sucked in somewhere, I've been through 2 litres of brake fluid already, but still no brakes. At one stage the car behaved like a smoke grenade when I started it. I disconnected the servo pipe from the inlet manifold - no more smoke. I can hear the brake fluid slushing in the system when I pump, but cannot get rid of the air! Any suggestions?

 

Welcome to the forum Scooterboy,

I've moved your question from General Tech Help forum to MKI/MKII forum. Members here with the same model as you have will be able to help.

When you 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

 

Possible clue in the 'disconnected the servo pipe' bit, - sounds like a possible leak of fluid into the servo pipe? An 'Eezi-bleed' vacuum gadget should - work one that either sucks the fluid through and out of the bleed nipples or pushes it through from the reservoir sometuimes using tyre pressure etc......It is possible you have something wrong with the servo if fluid is getting from there to the engine intake and making it smoke, ie what made you change the master cylinder seal in the first place?....? Hope this helps, Allan

 

The brakes were pulling to one side, replaced the brake fluid, which then leaked out the master cylinder. Replaced with new seals and started the bleeding process. Cannot swear that the servo was feeding smoke into inlet

 

Although the original problem of pulling to one side could have been caused by air in the system due to the fluid getting too low in the Fluid Reservoir or a leak, it could also be a sticking Caliper Piston which is common on older Jaguars.

In either case, you now appear to have a leaking Servo or associated Vacuum Reservoir or Check Valve which must be fixed before you can further investigate braking performance.

Any indications where the fluid is 'sloshing' around?

Graham

 

I bought a Gunsons pressure bleeder today, worked like a charm. Got the pressure back on the brakes and then reconnected the servo pipe - back to WW2 and smoke grenades!

Seems like I will have to either drive without the servo (not a good idea) or pull it out and start all over again.

Thanks everyon for your help

 

You're making progress.

Mk2 Servos and Servo Repair Kits are becoming more difficult to source. I turned up this supplier in California listing OE, Exchange, Repair Kits and alternative uprated Girling Servos:



Graham

 

Definitely you need to rebuild your servo, the seals wear out and it leaks brake fluid internally. My main vacuum piston was full of brake fluid, not so much that it was being sucked into the engine though like yours.
But enough where all the mystery brake fluid was disappearing too.

Two more hints, bench bleed the master cylinder when it comes time to do so, if you haven't considered that.

When bleeding the system I like to use Teflon tape on the bleed nipples, this seals the threads to keep air from re-entering the system when bleeding (even with a vacuum bleeder) and it also keeps out dirt/moisture/salt etc. when it's on the road.

 

Thanks again. Is there any hope that I just need to replace the slave (servo) seals and is there a way to get to the kit without pulling the whole servo?

 

It's a bench job.

Here's the relevant section from the MK2 Service Manual:

MK2 - Servo Unit.pdf

The exploded parts diagram on L24 could be useful.

Graham

 

Thanks for the diagram GGG, I was going to post a screen shot of that after work, but you got here first.

Scooterboy, number 46 in the diagram is the main culprit of the leak and all the smoke. Number 15 also wears, but it doesn't much so it won't be as worn, but you will want to replace that _ as well as the seals in the main brake cylinder.
The air valve diaphragm should be replaced as well.

The whole servo unit is removed from the fender-well area. Problems you may run into are: removing the machine bolts that are directly into the fender well that hold the protective shield in place _ the rest are just big Philips head sheet metal screws.

The bolts mounted on the actual servo shield that help hold the servo in place are exposed to the elements and can be quite rusted. The servo is rubber mounted with these bolts/nuts. Take care loosening these, if you start to turn the actual bolt, when trying to loosen the nut, it can be quite difficult to remove the unit if the bolts start to turn.
Jaguar has put some locking tabs in there, but they are quite weak.

The locking tabs are 18A in the diagram and the bolts that you do not want to spin are 18. The nuts are number 19 that are exposed to the elements.

Here are some useful links, I have never dealt with any of these sources, so I have no idea how reputable they are, but I plan to buy the seals from L&J Spares.

http://www.jlspares.com/sealkits1.htm

http://www.ebay.co.uk/itm/Jaguar-Mk2...-/281163735302

http://www.ebay.co.uk/itm/Jaguar-Loc...-/271272539997

My servo all in pieces...

https://www.jaguarforums.com/forum/m...r-bits-101644/

 

Hi all

Thanks again for all your assistance!

Guess what I'm doing this weekend? Will keep you posted.

Adie

 

Have a fun weekend!

Post photos if you get the chance to take them.

Graham

 

Just some advice, ANYTIME you remove or are installing a new master cylinder, you need to do a bench bleed on it to avoid going through two hours of bleeding and buying more brake fluid

 

Hi
Took the Servo out, struggled a bit with the 8 bolts and one of the brake lines, but got it out eventually. Guess what, all the brake fluid was in the servo and the vacuum reservoir!

I haven't attempted a self-repair, dropped it off at a reputable brake repair (Wingate Motors) and they said it was a no-brainer for them (I gave them a copy of the repair doc you guys sent, just in case). Hope to have it back tomorrow and then we go for it again!

Can't wait to have "Me Julie" back on the road. Will have to take her for a long run, to stretch those legs and burn off the fluid in the engine.

Adie