Front Brake Caliper Stuck

[davidr]

I've had a failure to proceed!
On the way back from the Wiltshire Region day at Stourhead this afternoon the steering on my 1996 Celebration started to pull to the near side and there was quite a bit of vibration coming through the steering wheel.
I pulled over into the nearest lay by and judging by the smoke coming from the front near side wheel and the unmistakable smell the brakes had got VERY hot.
So there we were, stuck in the side of the A303 with a knackered car. My guess was a sticky piston in the caliper not allowing the brake pads to move back when my foot came off the brake. Although I'm sure I could have fixed it enough to free the piston and get us the few miles home I didn't have any tools with me so a call to the 4th emergency service was in order.
The AA man was there just over 30 minutes later and we soon had the front wheel off, pads out and we're trying to see if the pistons would move. We did this by carefully pressing the brake pedal and seeing which moved. The inner and outer lower ones did so we jammed a pad between each and the disc to focus the effort on the others. The outer upper piston then moved leaving just the upper inner one. This was looking like our problem. Again we jammed a disc between the lower inner piston and the pad and so just isolated the sticky one. Pushing the brake pedal again finally got it moving. We worked it back and forth a few times just to loosen it up and then put it all back together again.
Now it's time for a tentative test drive, after making sure that the pads were faced up again so the pedal doesn't go to the floor the first time I tried to brake!
The idea was that we'd drive to the next lay by both to see how it feels and to see if any heat builds up in the near side brake. We did this with a infrared thermometer to compare the 2 sides.
Good news was that the near side was about 40 degrees and the offside about 30 degrees. We put the difference down to residual heat from the previous issue. If the brakes were still dragging then the heat would have been much more.
So we got home safe and sound after about an hours delay. Thanks AA!
Next job is to rebuild that caliper I guess!

[Brakebuster]

she's just letting you know she is as important as the V12 your spending all your time on , lol


BB

[davidr]

she's just letting you know she is as important as the V12 your spending all your time on , lol


BB

Yes - looks like I'll be doing a caliper rebuild Instead of progressing the IRS rebuild for my V12. Thankfully I'm not away much this week so a few evenings in the workshop coming up!
I've decided to refurb the caliper myself so have ordered a seal kit. I'll take a chance on the pistons being OK - I can easily replace one or two if needs be.
I guess while I'm at it I'll strip and repaint the caliper and it will be a chance to fit the braided brake hoses that have been on my bench for about 2 years and maybe I should upgrade to an EBC slotted disc and Greenstuff pads which means that I should do the other side as well etc etc etc.....
"While I'm in there" is all well and good but it soon takes on its own life!

[PaulGover]

...and maybe I should upgrade to an EBC slotted disc and Greenstuff pads which means that I should do the other side as well etc etc etc.....
"While I'm in there" is all well and good but it soon takes on its own life!

Don't forget to replace the stub axles, bearings and seals while you're there

[poprivet]

David, sorry to hear of your misfortunes.

It was good however to catch up with you again at Stourhead, maybe I shouldn't have told you about the time I cooked my rear brakes, it seems it gave your car ideas.

[davidr]

Paul - it was that kind of thinking that got me completely rebuilding the IRS on my V12. If I let it run away with me again then before I know it the front axle will be out and on the workshop floor! Then I'll have 3 cars in bits at once and nothing to drive! So no! Running repairs only at this stage!

Pop - yes it was good to see you and Mrs Rivet yesterday. I hope I didn't get you in too much bother for hanging around chatting when clearly your better half wanted a cup of tea! It would be harsh to blame you for my troubles. All I'll say is that it was absolutely fine on the way there! You may have to share the credit with Iain1980 - I was talking with him about brake dust on his shiny new alloys (care of BrakeBuster I believe) and mentioned that maybe one day I'll get round to swapping mine for EBC Greenstuff ones. "One day" is this week then!!

[Tintin]

Sorry to hear of your woes, David - I don't know what time you left, but you are always welcome to call me if you need local assistance with a breakdown - I think you have my number.

When I changed my front calipers last winter one bolt each side was well and truly seized due to corrosion between the steel bolt shaft and the caliper body. I sheared the near side bolt and had to remove the hub and get the remains of the it drilled out so I could remove the steering arm. Hope you have better luck!

Robbie.

[davidr]

Robbie - you must have some kind of divine insight!
I took the offending caliper off on Monday night with no real issues. I thought that if I was going to rebuild one side then I should do the other so I started to take that one off too. Bad move!
The long bolt that goes through the steering arm was obviously rusted solid in the steering arm and sheared off. Sorry if anyone was close to hear my reaction!
So now I've taken the whole upright, hub etc off and I'll be taking it down to Hollygrove tomorrow afternoon and Will is going to help me get it off.
When I get some time I'll post a few pictures and more detail.
Hopefully we can get some heat in and break the rust bond so we can pull the steering arm off. Then there should be enough of the remaining bolt to unscrew from the caliper. I can move the steering arm a bit so I'm hoping the thread will be free once we can get the steering arm off.
More news tomorrow night!

[ptjs1]

David,

Sorry to hear of your problem. Sadly not that uncommon on XJSs. I know that you know your way around the car pretty well, but you might get some ideas from this thread. Rather long but worth reading:

http://www.jaguarforums.com/forum/xjs-x ... 12-144321/

Good luck

Paul

[Brakebuster]

always advisable to use ' red rubber grease ' while reassembling brake parts , bit more friendly than using brake fluid its self
http://www.ebay.co.uk/itm/CASTROL-RED-R ... SwKtlWq9-q


BB

[oldtimer]

Pssst, Wonna buy a red mini

[davidr]

With plenty of heat (oxy-acetylene) we got the steering arm free and eventually managed to pull the steering arm off. This exposed more of the sheared bolt and the hope was that we could now get it out with a pair of mole grips. No such luck!
So we had to strip the hub and upright down by taking the hub off the disc and then taking the stub axle out. This allowed me to squeeze the disc off and then I just had the stub of the bolt stuck in the upright. A bit more heat and working it back and forth with mole grips and it eventually gave up.
Sorry no pictures but I was focussed on beating the bloody thing and forgot!
So now back to the original job.
I gave my calipers to my daughter's boyfriend who has a grit blaster at work and he's cleaned them up for me ready for painting and rebuilding.
One annoyance is that I ordered a new caliper bolt from David Manners on Friday (£5.40!) thinking that they'd do the sensible thing and put it in the post so I'd have it today (Saturday). Apparently that's too sensible and they've chosen the slowest and most expensive delivery method and it's coming on Monday via DPD. Brain dead or what? And they've charged me £5.50 + VAT for delivery!
OK - I'll stop ranting.
Next steps will be to check the condition of bearings, stub axles, ball joints , bushes etc. Yes - while I'm in there has taken over!

[J44EAG]

Delivery times and charges are a pain in my life, David.

Most of the major parts suppliers use carriers with minimum charges. British Parts for instance do just that. XJK are far off the beaten track and have no local postal facility. Therefore they have also to use a carrier. Consequently a £3 gasket can cost £10 with delivery so it is often worth ordering several new parts in order to make the delivery costs go as far as possible. It gets even worse if ordering from abroad. I`ve given up ordering from the US due to exorbitant delivery costs and the fact that parts can languish in a Customs shed in Langley for weeks before someone eventually gets them on the move.

If at all possible I will use ebay or Amazon suppliers. Delivery is often free and very rapid. I know it is not always possible to find the parts you need from those sources but it is worth a first punt before going elsewhere.

I have a well known aversion to ordering from a Jaguar Main Dealer. Whilst I can order over the phone from Dealers at Southampton or Chichester, they hold little stock and at best delivery is next day if you are lucky. Even with any discount that can be obtained, costs plus traveling can often make for a high final bill from those sources.

These issues I suspect become more difficult when it comes to parts for classic cars. Sources become more limited and at that point you can often find yourself over a barrel.

Sorry to hear about the seizure issues and the need for heat. If it is any consolation, I experienced similar issues extracting the lower front damper bolts on my 350. Corrosion takes no prisoners.

Mike

[XJR-S]

I'm glad I've read all of this and the links above before diving into a front hub job this month. Yikes!!! Thanks all.

[davidr]

Apologies! I've been rather remiss in updating this thread!
So, here goes

Here's the offending caliper

First I tried to push the pads and therefore pistons back to free the pads. One side was more difficult than the other so confirming the sticky piston theory.

On inspecting the pads it was obvious that they had got very hot so I decided to replace them.

It was evident that the smoke was the pad and its backing material combusting!