sticking caliper

[KEVIN47]

hi all , just wondering if anybody has had a problem with a sticking caliper , it started off fine the other day then started pulling to the right and i could smell the pads rubbing and by the time i got to my destination the brake pedal fell to the floor ( change of underwear needed ) i left the car for 90 mins and it seemed to be fine then the fault reocurred ,i have been told the failure was due to overheated brake fluid due to the sticking caliper . can anyone advise as to a remedy ,the car is a recent purchase and had been left standing for a while i have covered 500 miles ish since , also the anti lock light illuminates on occasions ,no other warning light came on on the day,
what a great car though ( mind you i feel i have converted to islam and gained another wife, beautifull but complicated )

[ptjs1]

Kevin,

Welcome to the Bulletin Board!

A sticking caliper is not an uncommon problem, but I wonder if that is really the problem. If the caliper sticks, it is more likely to stick "retracted" and thus not allow the fluid pressure to push the pads against the disc. This causes the car to pull to the other side as braking is only occurring on the side that is operating properly. This wouldn't tend to cause boiling of the fluid unless you were braking really hard.

If you've got a smell of brake pads, this feels more as if the pads are in constant contact with the disc and the temperature rise than transfers back to the fluid causing the boiling and the "pedal to the floor" syndrome.

Therefore, I wonder if you might have a pressure lock which is preventing the pads and caliper from retracting back from the disc when the pedal isn't being pressed. This type of pressure lock can be caused if you get an internal collapse of the flexible brake pipe (or even a kink in the rigid pipe). The flexible pipe can look fine from the outside but the inner walls may have collapsed, preventing the fluid from retracting.

Try raising the front wheels and getting someone to operate the brake pedal, release it, and then see if you can turn the wheels by hand as the pads back off. If one wheel is stuck (the one with the smelly pads) then you should start looking as to what is causing the problem.

I don't want to mislead you - it might be the caliper sticking open, but I think you might have a fluid lock problem.

Hope that helps

Paul Sinnott
XJS Registrar

PS If you haven't already, could you please enter your car in the register. PLEASE ensure you have ALL the requested info to hand before entering the car, including paint and trim codes. Tks very much

[KEVIN47]

thanks paul for your swift reply i will set to with some investigations ,
on a differant note you asked me for my cars colour code and trim code , i cant seem to work out where this is as the original service book is a tad worn , are there any codes on the car itself
thanks once again for your help if your in kent anytime i,ll buy you a pint
kevin simmonds

[Hosier77]

Paul is probably quite right, but also I have found calipers sticking after a long period of inactivity, on one occasion this was due to the dust seals (the ones closest to the pad that stop dirt getting in, not the main seals which are the ones that stop fluid leaking out) getting swollen and sticky. Luckily they were easy to replace once the caliper was free from its supports.
As an aside, on race cars the dust seal is usually ommitted due to the heat causing it to bind, the drawback is that road dirt attacks the main seal thus requiring constant cleaning maintainance.

[xjsaint]

Hi,
I had exactly your problem on my 86 XJS 3.6, unfortunately I had to drive home and at a certain point the caliper started loosing liquid.
Now the car is home and I am in the process of removing the calipers and see what happened...The conduct may be the problem. I had replaced the fluid a few weeks before and I suspiciously experienced that in the rear calipers the fluid won't come out. I had to press really hard..
Any suggestion,?

Always welcome.

Valter Italy Rome.

[Telsmoneypit]

Valter, please add the year of manufacture to your signature.

It helps if you indicate NON ABS or ABS.

Bleeding Non ABS is easy...

ABS is a pain in the arse.

Tel

[Telsmoneypit]

Apologies Valter. You indicated 1986 MY in the main body of your post. I tend to look at the signature for vehicle information and I missed it. Sorry!

So, non ABS...

I'd suggest that as your car is now 22 years old, it's time to do a complete overhaul of the braking system. Don't be scared! Non ABS is easy. However, here in the UK, it's late and I have had a hard day fighting my X-Type. I will advise you later...

G'night.

Tel

[xjsaint]

Hi there,
and many thanks for reply:
Yesterday I tried locating the bolts for the removal of the calipers but...they are really well hidden, I don't have a safe way to work under the car so I think I'll go for the complete IRS removal and overhaul of the rear breaking system together with a general look also to the other parts of the breaking system,

I don't have a way to work under the car safely this is why I think the removal of the IRS is easier and safer.

I'd appreciate a your comment.

Regards,
Valter

1985 manual 3.6 coupe

[almcl]

Valter

Absolutely agree that getting the IRS out will make it a lot easier to work on, but if you don't have a safe way to work under the car, how are you going to extract the IRS?

The rear of the car needs to be raised almost 50cm, the handbrake cable, prop shaft, brake pipe and exhausts all have to be taken apart or disconnected and then the bolts securing the cage removed and the cage lowered (on a jack, usually.) All this while supporting the body of the car on axle stands or similar, under the jacking points, according to Jaguar's instructions.

[xjsaint]

Hi,
I replaced the hand brake shoes some months ago and that was hard but I worked it out,

I will use that experience to first put the car on supports and detach all the fixings as you described, including main transmission shaft, these are all much more reachable then the Brakes calipers, then I'll put the car on two stands ( slightly rising the car), Fit a support under the differential, remove the two wheels in order to make the whole lighter, and then raise the car using two people at the same time from the two sides. At this point I will remove the whole Cage from one side, not from behind (I saw doing this from a guy in the USA) it requires less raising of the car.

It should work. A few operatons that require two people ( like raising the car simultaneously from 2 sides) I will have the help of my father.
Unfortunately the option of working from under the car looks impossible. I was able to remove the Handbrake calipers because the retainiing bolts are just in front of the operator but the main brake has the bolts aside the differential, impossible to reach....

It looks complex but I am studying the details and seems easier than the other option.

Plus, it is a good opportunity to clean all the parts and check them.

Every suggestion is REALLY well accepted.

Thanks for reply,

Valter, Rome Italy

[kelsham]

Valter, Keep in mind that the rear flexible brake pipe often swells up internally and this causes the rear brakes to stick on.
I removed my rear subframe and rebuilt the brakes before I discovered this to be the true cause. I was a little put out as I had not needed to do the work ,only replace the pipe.

If you intend to remove the rear end cut the pipe first and examine if it is swollen and deformed. regards Kels.

[xjsaint]

Hello,
many thanks for reply:
I'll check that tube out, nevertheless, I have oil coming out from the rear caliper on the passenger side, not from the lines but from the caliper itself. I hope is just a seal problem, I'll see this tube line when I will have access to the caliper.
It all started with the pedal going to floor (almost) leaving a last inch of breaking force, but no liquid loss. . Just I remark this problem happened after a plane highway drive, no brakes at all. The whole was accompained by the classic smell of breake shoe coming from the sick side (passenger).The next day, it was all ok, the problem had disappeared.

So after a week we ( me and my wife) were invited near Rome (Orvieto) and I decided to go with the XJS. With surprise after 100Km of highway I experienced the same problem....pedal to floor, this time I was quite far from home. After a day with our friends I decided it was time for going back home....slowly...very slowly. At about half way I stopped at a gas station and checked breaking and looking under the car...oil was dripping at every brake pedal press. I limited the breakings to home and I drove it until my garage at home. Now it cannot go out until it will be ok. I think this will be my Summer-Autumn work.
I suspect, that an old Caliper seal had locked slightly the piston toward the disc, thus the warming up of the disc and the smell; conseguently, the heat has destroyed the pistonn seal thus the oil coming out of the caliper. I hope the caliper and piston don't have distorted enought to require a replacement of the whole assembly. I will let you know btw.
What do you think about the mechanical distortion?
In a way I can't wait to do this job but unfortunately, we are in the process of renewing a room in our house and I have a very pretending wife in this moment...jaguar can wait!!
Thanks for your poins, they are always wellcome.
Regards,
Valter

[xjsaint]

Hi all, have a look to the this post on the forum, it contains some more details on the work I performed this summer on the brakes subject.

http://www.jec.org.uk/forums/viewtopic.php?f=44&t=1794

Thanks,

Valter

[PaulE]

My car had its front brake pads changed in front of the hotel in Strasbourg on the 2009 Entente Cordiale by 'the maestro' Ken Jenkins, and they are now finally sorted . He used pads for a Renault Trafic van as they are exactly the same as the Jaguar ones. Having had such disastrous experiences with anything Renault over the years I was apprehensive when I saw the packaging, but Mintex are the producers - a brand to be trusted. Check them out if you need any - they are no doubt cheaper then Jaguar branded ones in Rome. All the best with you problems. Paul.

[ng4xjs]

I'm not scared. I have a Renault battery in mine and it's great :

Nick