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Mike, Jaguar Technician
Category: Jaguar
Satisfied Customers: 39198
Experience:  Tech Expert
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Hi, i have a 1989 XJS convertible with the 5.3 litre engine.

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Hi, i have a 1989 XJS convertible with the 5.3 litre engine. It has the Teves ABS system on it.There is no loss of fluid or leaks anywhere on the system, but I have experienced on several random occassions that the brake pedal, whilst there is pressure there and the brakes do apply, the brake pedal gradually goes down to the floor. Obvoiusly this causes me to panic and I do pump the pedal , it does not seem to make the pedal any better but the brakes do apply. Any ideas would be very much appreciated.
Kind regards,
***** *****.
Ps. I have just driven the car to the Le Mans classic and drove the car for two laps round the circuit.
Hello Doug - and Welcome..

Given your symptoms - so long as you have no leaks anywhere on the circuit as you mention - then the fault is the brake master cylinder.

Whats happening is - every now and then - at the times you say the pedal goes to the floor- the seals inside the master cylinder are either turning on themselves or simply letting the fluid go back on itself inside the cylinder.... hence, when you press the brake - rather than the fluid being pushed down the line fully as it should - some is going - and hence the brakes work - but some is being returned back on itself -and hence again when that happens - the pedal will go down to the floor.

So its a case of attending to that Doug - either repair or replacement of the brake master cylinder to cure this issue for you.

If there is anything more by all means get back to me and we can carry on...

** >> Meantime >>>> Please do click on the "OK/ Excellent ratings" for me - Thank you in advance for that...

You can and are most welcome to get back to me anytime you might need - clicking the OK ratings does not close you out at all..

Kind Rgds, MIKE.
Mike and other Jaguar Specialists are ready to help you
Customer: replied 3 years ago.

Sorry I could not reply before, but I was out driving a coach all day yesterday and did not get home until 1.00 am this morning. I take on board what you have concluded and I have to say that has been my personal opinnion from day 1. Unfortunately I cannot find a supplier who has an 'O' ring kit.

Kind regards,


Hello there Doug -

No problem at all I understand that - people have things to do / places to go / a living to make etc ;) It was a lovely day for coach driving !

I dont know whether this will help you any at all Doug - but I have a couple of contacts - you may have already come across them - try them for the seals - of the master cylinder if needs be - prices should be better than local sources..

The first one I have in mind is HERE.. 2nd is HERE - and another HERE.

I hope that helps a bit Doug -

All the very best - MIKE.
Customer: replied 3 years ago.

Hi Mike, you must have thought I had emigrated, but no I am still here. Coach driving takes up a lot of my time this time of the year and the odd day out to keep the peace at home has to be endured as well. I tried all avenues to get either a new master cylinder assembly or an O ring kit but nobody had got either, the answer was always "no longer available". So the only option left was a second hand one, which I obtained on Friday by driving a 200 mile round trip. This was fitted on Friday afternoon and then came the next snag, to bleed the system.With a great deal of help from my boss and thecoach garage fitter, this was acheived this morning, so the car is back on the road.

Thanks for your help,


Hello there Doug -

No problem at all Doug - at least you have had nice weather for that job Doug ;)

Well Im very pleased to hear its sorted and ok for you - Its always a problem getting parts eh when cars get older... so Im glad you managed to get a good one.. good job done!

All the best Doug - Drive safe.. and you know where I am if you ever need anything else..

Best Rgds, MIKE.