O/S/R Brake Locked On.

The metal pipe is £15 so I wouldnt worry too much if you feck it up taking the caliper off!

Billy, no arguing that £15 is small change in terms of the more usual expectations of Porsche car parts... But being an old codger, I was ever working on a low budget and with a bit of effort if a part could be saved while working on my old car at night, that perhaps equated to me not having to make alternative arrangements for transport to get to work the next day.. and yeah, I appreciate things are very different today...(-:

Bottom line for ME is to try to avoid dependency, be that on the availability of spare parts from parts suppliers the postal/delivery service or saving me having to travel and stand in queues to attempt to acquire them, any and all of which can be frustrating, as it seems might be the case with the already ordered and new calliper...? Hope not.

Disturbing brake parts on what is an OLD vehicle and has has lived in the UK climate has potential to damage hard to replace components that if left undisturbed may carry on for years ably performing the task they were designed so to do, thus seeking minimal disturbance can at times be a reasonable path to follow..? Sorry Phil I can not remember the clip arrangement exactly but think it slid over a bracket in the suspension arm and into groves in the metal termination point on the flexy hose, quite a strong set up if I remember correctly but if to be disturbed I suspect I would want to have a replacement clip to hand before doing so...?

If you take enough care in trying to unscrew the pipe nut, as described earlier and reach a stage where the nut can run along the length of the pipe reasonably freely, then if the nut is unscrewed and pulled back dependant on the condition of the pipe it can be bowed along as much of it`s length as possible to avoid any chance of kinking it to withdraw it from the calliper.... HOWEVER, if you have decided to remove the calliper, then no point in bending the pipe to extract from the calliper it until the calliper is free to move which then might entail less of a bend to be inflicted on the pipe...?

The bleed nipple.... hmm..? Well even if you end up binning or trading your calliper, I suspect you would be best to have a go at this calliper given you may in time if not now, seek to bleed other parts if not all of the brake system... BTW, my offer of a fiver still stands... CASH...(-:

Of course you will have perhaps wire brushed and cleaned the nipple and given it a few good sprays of the releasing agent of choice over a day or two..? Fortunately Porsche nipples are pretty sturdy, and with all potentially corroded fixings, shock or/and heat can play a part. I have used gas welding gear to heat the calliper to red at the area of the nipple to break the bond betwixt calliper and nipple, and it did not damage the calliper in any way I am in no way suggesting you should get involved in that Phil even if the gear was available... brake fluid is very flammable.

Shock, a well aimed hammer blow DIRECTLY on the end of the nipple can shock it a bit and likely deform the bleed hole to some degree, but if it helps shock and thus assists removal of the nipple no big deal...? I guess the other thing is to have the VERY best fitting ring spanner you can get on to the nipple, and corrosion of the hex can play a part here, thus an AF, Whitworth or other spanner may fit tighter than the formerly correct size, might even have to be tapped on to fit tight..? Applying pressure back and forth on the spanner can help release the bond a tad and another dunt with a hammer on the nipple end, if it starts to move another spray of stuff can perhaps now penetrate a bit more, working the niple back and forth can free things up more until it is ready to unscrew the whole way.... Sure you can refit the old nipple with the damaged end even drill the end to clean it up a bit, or buy a new nipple if you feel the need... (-:

Of course buying all new parts is the correct way to tackle any job... From that which I have read on this forum it seems even 992s may be lying off the road with next to no miles covered as the result of spare parts required to repair them being unavailable...??? IF so, what are the chances for 30 year old cars.... Yeah if you are intent on running OLD machinery then perhaps alternatives might be worthy of consideration...??

Consider if you will, one new calliper brake pipe and perhaps clip is an improvement but how many other parts in a braking system are likely to be are circa 30 years old and how many other old Porsches might occasionally be driven at high speed with components perhaps older than their drivers... Hmm..?

Just thinking in type.. :?:

The clip for the flexible pipe is a U shape .. you lever it off upwards with a large screwdriver , lever between the pipe and the clip .

Once removed you should .. in theory have just enough wiggle room to get the caliper off the disc ... hold it though .. don't let it hang .

If the brake pipe nut is turning the pipe then its seized .. pretty normal but you can twist the caliper off of it .. in other words don't undo the brake nut other than to crack it free .. turn the caliper ...

There is a small amount of give in these pipes .. flexible to a limit shall we say .

Options if not .. you work your way backwards seeing which pipe will actually come undone .. you then replace every pipe from there forwards to the caliper .

I'm afraid this is pretty normal stuff with these cars .. it's not hard as such but then i would say that wouldn,t i lol .. sorry

You will need a clamp for the flexi pipe ... don't have to but be quick if not .

not sure why you need the nipple undone if you are replacing the caliper ?

Once all finished .. job done .. engine running and stand on the brake pedal for 1 min .. if no movement in pedal and no obvious leaks then your sorted .

Last comment .. you need to drive it more young man .. cars like to be driven .

As ever, thanks for the input guys.

The nipple on the dud caliper doesn't actually need to work but Luddite suggested (very helpfully) that I might like to practice freeing this one in preparation for trying to bleed the other three brakes.

If the other three are anything like this one, I'll need all the practice I can get before tackling them!

Aghh i see ..

well for this particular fault you don't need to , if doing a brake fluid change then you would .

Smacking down on it with a hammer is one idea .. for me .. i smack the spanner on it with my hand and kinda feel if it's going to come undone , not something i can really help you with there i'm afraid so practise on this is a very good tip .

These do tend to come undone though .. a ring spanner or a brake pipe spanner .. this has a fatter end on it .

Failing that a ratchet / socket .

Got to admit i'm quite enjoying this thread .. not often i post so much on a single one

Following advice on this hallowed thread, the brake nipple on the dud caliper is now turning sweetly.

The upper (relatively accessible) caliper bolt has been persuaded to relax its grip on the caliper and should be removable when the time comes.

The lower (relatively inaccessible) caliper bolt won't allow me to use anything with the same leverage I used on the upper bolt but we'll see how it goes when I get serious with it.

Things are certainly progressing – but there's still no sign of my new caliper.

I emailed Design911 first thing this morning to ask what was happening and they promptly replied to say that my caliper is "on order". I immediately replied to ask them when they expected to have it in their possession but they have not yet replied to that question.

Phil, while you are in calliper limbo, why not have a go at freeing off the stuck piston as suggested... what have you got to loose...? I guess the risk is you could blow a corroded brake pipe somewhere, or show up a flexy hose with an issue...though as I have typed better to do that now as opposed to when you are trying to stop in an emergency.... On the other hand you might learn something more about callipers with stuck pistons... :?:

Phil, you need to go looking for an alternative to the caliper you have on order if you want to use your car in the near future!

Luddite said:

why not have a go at freeing off the stuck piston as suggested.

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I tried it a few days ago but it didn't work.

The immovable piston remained immovable and fully retracted into its socket.

The other piston will move outwards under pressure from the pedal but won't retract under its own power: in fact it's so reluctant to move that it's very hard to push it back into its socket even when I use the special tool.

Initially, I thought it might be a case of simply "unsticking" the pistons in a single glorious moment, after which they'd move as freely as they ever did – but even the one that will move is only doing so under gargantuan force. Does that mean the caliper is never going to work properly without a strip down and (possibly) new pistons?

Billy Bumpsteer said:

Phil, you need to go looking for an alternative to the caliper you have on order if you want to use your car in the near future!

Click to expand...

I fear you might well be right, Billy. :x

Phil, good to read that you tried... (-: If you could not move the stuck piston using hydraulic force, then I doubt you would ever do so with an air line (were that available) which given the measure of seizure evident could have been dangerous to attempt.

Never known a seized piston to be able to resist real pressure applied to the brake pedal but hey, every day is a school day... (-: Of course you need to ensure that there is no air or flex in the system, and pack the disk to stop it from flexing thus the only component with the possibility of movement is the stuck piston..? Hope you were able to press that pedal like your life depended on it just as tends to be the case in an emergency stop... but as you have been working on the calliper perhaps some air is in the system working against you.

I think it is possible to find stainless steel pistons for Porsche callipers, which may be more suitable for use in seldom used cars..?

Pistons do not retract "under their own power" they are batted back marginally by the disc hitting the pad when the pressure on the brake pedal is released... If they retracted.. then you would have to displace a large amount of fluid for the pads to once again make contact with the discs.... Kinda like when you fit new pads you have to pump the pedal a few times to then make the brakes work, after which they operate as expected.

When you park the car, you naturally put on the brakes to stop it, at which time the pads are in contact with the discs, they do not retract but stay in contact if the discs are wet at the time then that adds complication if the car is laid. IF the dust seals are also damaged and the car has been run that way on damp or wet roads, then that adds further complication, add to that if the brake pads are worn down, then more of the machined surface of the piston may be exposed to the elements and you are into a brake overhaul as opposed to fitting replacement pads and a general clean up of expected corrosion on the calliper and pins etc.

By way of increasing understanding.... Once you have a replacement calliper to hand and have determined there is nothing to stop you from removing the problem calliper by way of irremovable fixings but with all still in place, if you extend the piston that does move and push back the dust seal, you will no doubt then see some of the crud that is restricting it`s movement which can be cleaned off, and which if cleaned and a splash of WD 40 applied during the clean up process might then be easier to push back into the cylinder..? If that process is tried a few times the piston may be less reluctant to be parked back in it`s cylinder... Of course the other likely restriction is the outer ring of the calliper that holds the seal in place and which you can not see as it is hidden under the dust cover.... However if you wish you can pop the piston out and view the whole assembly to increase your understanding..?

Of course YOU do not have the training, certification or the proper facilities to be working on your brakes, and you really should employ professionals to work on safety systems that could affect you and other road users.... So best stick to polishing, though do check that the polish is Porsche approved.... :?:

Had I been so restricted I would have learned far far less than I think I know..

Thanks for the tips and advice, Luddite.

On the subject of obtaining a new caliper, it seems Billy Bumpsteer is very much on the ball when it comes to the subject of their availability.

I've just received an email from Design911 saying their suppliers tell them that the caliper is on factory backorder with no ETA. Accordingly, I've cancelled the order and they've promised me a refund in 2 – 3 days.

Also, I've just been to my friendly neighbourhood motor factors to buy 2 litres of brake fluid and, while there, I asked for a price for a new caliper.

The guy made several phone calls and came back with the depressing news that none of their suppliers have one in stock.

He did however say he knows someone who is very good at reconditioning calipers and he gave him a ring. He then returned to say the guy hasn't done this model of caliper before and so he sent him a picture of it to give him an idea what's involved.

He's going to phone me with news.

On the subject of the caliper, a potentially very important question has just popped into my mind: when ordering a caliper for the "right-hand side", that does mean the right-hand side as judged by somebody sitting in the driving seat, doesn't it? I mean the side that's commonly referred to as the offside or driver's side?

I'd be very upset if, after all this trouble, a brand-new caliper turned up at my front door and it was for the rear passenger side. :sad:

All sides are as sitting in the car, you need a right hand one, they are available new but at £200 + vat, the core charge wouldnt be a problem as you have an old unit to return, it wont matter if its U/S as long as its a caliper!

Google 91135242600 UK new ATE caliper

Thanks for the tip, Billy.

Design911 have just refunded my payment of £221.99 – that was very quick, wasn't it?

I've just ordered an ATE caliper from an eBay seller, Mister-Auto–UK for £238. They didn't ask for the old caliper in exchange.

They've got more than 52,000 feedback points, 97.4% positive. I checked out the negative ones and they seem to be concerned with lengthy delivery times rather than outright scamming.

Prior to ordering, I sent them two emails asking about compatibility and availability.

Their replies to both emails were positive and lightning fast!

Their eBay page says they're based in Coventry but one of the negative reviews says the parts are actually sent from Germany.

Estimated delivery is a week on Friday/Saturday but these estimates are normally quite generous and most of the products I've bought on eBay are delivered well before the estimated date.

Still, knowing what we know about almost non-existent availability, I'm very happy to wait 10 days if the right part turns up.

The true UK supplier that should have been flagged up on the first page of a Google search could have a new caliper tomorrow ready to ship!!

Anyhow, hope all works out ok for you next week!

Billy Bumpsteer said:

The true UK supplier that should have been flagged up on the first page of a Google search could have a new caliper tomorrow ready to ship!!

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The 1st website on the Google search was buycarparts.co.uk who wanted £406.98 -20% discount = £325.58 and they do say the item is in stock.

The 2nd website was bestpartstore.co.uk who wanted £325.84

The 3rd was onlinecarparts.co.uk who wanted £325.77

The 4th was eBay and the link took me to a page saying that they were sold out.

The 5th was spareto.co.uk who wanted £333.12 and promised delivery in "about a month".

The 6th was type911.co.uk who wanted £200 plus VAT plus delivery plus £50 core charge, refundable when I send them the old caliper. They didn't have any new ones in stock.

The 7th was eurocarparts.com who wanted £349.99 - £119 discount + core charge of £55.99 = £286.98 but they have yet to reply to my email confirming compatibility and availability. They have 44,000 feedback points with 99% positive but some of the negative feedback remarks are pretty discouraging – lack of communication being among the complaints.

If Euro had replied to my questions promptly, I would probably have gone with them.

All in all, Mister Auto's price of £238 with no core charge and thus no need to send the old caliper (probably at my own expense) sounds like a pretty good deal – as long as it turns up!