early turbo front caliper swap (new vs. old calipers).

[chrisg]

Chris a few answers to your questions:

Wear indicators: The wear indicator for one pad has disintegrated. Is there any disadvantage to leaving these out? The pads are very well worn yet there is no wear indicator lit on the car. It doesn't seem to serve much purpose if you are in the habit of keeping an eye on your brake pad wear anyway.

IMHO I wouldn't bother with them if you're checking the pads on a regular basis. All I'd do is ensure you leave the 'stub' or connector in the barrel connector thingy to keep muck out of the electrics, simply chop the cable off at the connector. I've had my Turbo like this for years - learn to live with the wear indicator red on the dashboard. Re-use of washers for caliper bolts: The washers for the caliper bolts are a bit warped. I assume I should replace these? I guess the bolts are cheap enough as well to be worth replacing? I would they're not massively expensive either OPC or standard metric bolt, not with the hassle of them getting stuck or rounded off. o remove the calipers I clipped the brake line with a brake hose clamp and then rotated the removed caliper until it came off the thread - nice. However, when I reverse the process with the new caliper on the thread fully it is not at the same orientation. To get the brake calipers on and the brake hose back in place as before I will need to either tighten the hose further in the caliper (it is not yet torqued but is reasonably tight) or twist the line somewhat. What should I do?? It seems like the thread on the new caliper must be start at a different angle to the old caliper? This is one way of doing it, TBH you're going to have to bleed the system anyhow, I would just disconnect the flexi line where it meets the hard line , connect it into the calliper then do it back up to the hard line and ensure it's not twisted. Do you lines have a small copper washer between the fitment and the caliper ? I've bought some yellow stuff pads, after much deliberating. I had green stuff pads before and had no problems with them (the way I drive) on track days until they wore down. I admit budget came into it! Anyway, although the slider plates on the new calipers look very clean (and new), the pads do not slide in. There is probably not much in it - it might just require removal of the paint, but I suppose I should take a file to the edges of the pads (the metal, not the pad material) until they fit? In which case, how freely should they be able to move? Should they be snug, so they require a bit of working to get them in? Or should they move freely in the caliper They need to be free to get in and out of the caliper, yes take a small file to the backing edge both top and bottom to ensure they slide in nice and freely. I should add that there are some subtle differences between the calipers - the old one had 'porsche' embossed on them, the new ones just have it printed. Also the hinged retainer for the pads folds upwards on the new ones - it folded down on the old set. Presumably these are just minor changes relfecting that the new calipers came off a younger car (an S2). Errr no..... Both the 944's Ive had (current 951 with M030 calipers) and an S2 (G reg) teh clover leaf folded upwards ie the pivot point was at the bottom. I would check both calipers for direction - the brembo calipers usually have an arrow showing the rotation of the wheel relative to the caliper - the bottom and top pistons are slightly different. Its vaguely possible that a previous/ last owner switched the calipers ? Just check that the bleed nipples are at the top of the caliper and the cross over pipe is at the bottom. If you need any assistance or want to chat happy to take a phone call ? 07540 193874 Yours Chris

 

[amrbose14]

Hi all,

finally getting around to fitting refreshed calipers to the front of my 87 turbo. I have a set of 'refurbed' calipers from Jon Mitchell (on an exchange basis). They have cleaned up some S2 calipers for me, and cured the plate lift - new slider plates, nipples etc. I finally settled on this as it seemed like what you got with a lot of caliper refurbing services was the same but they charged you more for a nice paint job. And this way I got something from someone I could trust.

I finally got the caliper bolts undone with the aid of a car jack (this is the drivers side - I don't think this will work on the passenger side!)... I have few issues putting the new calipers and pads in and would appreciate some advice.

1. Wear indicators: The wear indicator for one pad has disintegrated. Is there any disadvantage to leaving these out? The pads are very well worn yet there is no wear indicator lit on the car. It doesn't seem to serve much purpose if you are in the habit of keeping an eye on your brake pad wear anyway.

2. Re-use of washers for caliper bolts: The washers for the caliper bolts are a bit warped. I assume I should replace these? I guess the bolts are cheap enough as well to be worth replacing?

3. To remove the calipers I clipped the brake line with a brake hose clamp and then rotated the removed caliper until it came off the thread - nice. However, when I reverse the process with the new caliper on the thread fully it is not at the same orientation. To get the brake calipers on and the brake hose back in place as before I will need to either tighten the hose further in the caliper (it is not yet torqued but is reasonably tight) or twist the line somewhat. What should I do?? It seems like the thread on the new caliper must be start at a different angle to the old caliper?

4. I've bought some yellow stuff pads, after much deliberating. I had green stuff pads before and had no problems with them (the way I drive) on track days until they wore down. I admit budget came into it! Anyway, although the slider plates on the new calipers look very clean (and new), the pads do not slide in. There is probably not much in it - it might just require removal of the paint, but I suppose I should take a file to the edges of the pads (the metal, not the pad material) until they fit? In which case, how freely should they be able to move? Should they be snug, so they require a bit of working to get them in? Or should they move freely in the caliper?

I should add that there are some subtle differences between the calipers - the old one had 'porsche' embossed on them, the new ones just have it printed. Also the hinged retainer for the pads folds upwards on the new ones - it folded down on the old set. Presumably these are just minor changes relfecting that the new calipers came off a younger car (an S2).

Sorry for the over long email. The job is (as usual) taking much longer than it should do as well!

cheers,
Chris
------------------------------
1987 944 turbo.

 

[amrbose14]

Arse.... fitted on the car with the nippples at the top and the pipe at the bottom.... the directional arrow is in the wrong direction (down). My guess is that JMG put the copper pipes and bleed nippples on the wrong way around. They did this on both calipers - so consistent at least! I should probably give them a ring tomorrow. I guess I can just swap the pipes and nipples back around? Although there could be some problems sealing the copper pipes I suppose... This may also explain why the calipers are not rotated in the right way to fit neatly with the brake hose? I clamped the hoses because I only have room to put one caliper on at a time. I have to move the car over to do the other side, and my driveway is steep! So I want to just bleed the one caliper and have good enough brakes to reposition the car without rolling out into the road. Chris

 

[Paul 290T]

The callipers have uneven piston diameters. I presume that is because Porsche/Brembo decided that the force on the pad needs to be slightly higher on one half of the pad than the other. Whatever their reasons and whichever way round the force distribution is intended to be, I'd swap the callipers back to the correct side.

 

[chrisg]

All things being equal, you should easily be able to swap the bleed nipples and crossover pipes with ease, particularly as they'll have been out recently ! HOpefully the calipers should still work OK and you can swap things over when you get chance.

 

[amrbose14]

Oh well, there goes the plan of getting one side completely done over the weekend. Never mind. At least I feel I am on top of the job now and still glad I've tackled it myself. It's a learning experience! thanks guys. Chris - I may keep your phone no handy if that's OK. Chris

 

[chrisg]

Chris you're more than welcome ! Feel free to ring anytime for advice/ listening ear. I always find it's easier to talk it through with someone on the phone than by e-mail and helpful if it's someone who knows the car/ problem ! Chris

 

[dunc]

IMHO I wouldn't bother with them if you're checking the pads on a regular basis. All I'd do is ensure you leave the 'stub' or connector in the barrel connector thingy to keep muck out of the electrics, simply chop the cable off at the connector. I've had my Turbo like this for years - learn to live with the wear indicator red on the dashboard. Chris

Just a quick note on this, if you leave a bit of each wear indicator wire when cutting it at the plug you can then join the two wires (solder and heat shrink, or crimp connector?) and this over rides the dash light. Or if you've only got the problem on one side you can do this and the wear connector will work on one side only which should be fine. Dunc

 

[zcacogp]

Can't add anything much to the discussion thus far apart from to add that the rotation of the calipers such that the flexi hose is a bit twisted isn't a problem. The flexi hoses on my S2 are very long (I imagine they are the same on a turbo) and there is more than enough slack to take up some twist. I'm intrigued by the fact that the retaining gate hinges the wrong way. I guess this part and parcel of the 'side' the caliper is intended to be in, and this is determined by the arrangement of the big and small caliper pistons, the direction the gate hinges and the way that the nipples and crossover pipe are arranged. The calipers should have been assembled such that the crossover pipe is at the bottom when each caliper is on the correct side of the car, and hence if you swap the crossover pipe with the nipples then you will have a caliper that is wrongly assembled. Check that the two calipers are mirror images of each other (i.e. that JMG haven't sent you two for the same side) and then fit them accordingly. Agree with Dunc about shorting the pins out on the wear sensor. Solder and heat shrink is the way forward. If you are a fairly active home mechanic you'll know how much meat there is on the pads and not having the wear sensors makes the caliper assembly much quicker and tidier. (Chris, do you really drive around with the warning light on all the time? That would drive me nuts!) Oli.

 

[chrisg]

Oli In answer to your question Yes ! I can't be fussed with wear indicators on a car that does < 5k miles a year !

 

[944Turbo]

Assuming the compound is still similar you will want to get those yellows really hot, I have them in the coupe and they squealed and grumbled until I really cooked them. Tony

 

[Bob]

I'd be very worried if I had to grind my brake pads to make them fit into a freshly refurbed calliper - they should slide in and out by hand. The fact that the pipes and nipples are in the wrong place is also cause for concern, have you managed to change them over yet?

 

[amrbose14]

I've now managed to swap the pipes and nipples around (after a ring to JMG to discuss it - and then bought a brake spanner - oh why did I not have one before?!) and have fitted the correct caliper loosely to the drivers side. All looks good. I'm getting some new caliper bolts and washers from my local OPC tomorrow, so everything seems to be going smoothly now. Another good thing is that the caliper now sits nicely with now extra twist in the brake hose, as it should. I can't remember who had suggested removing the wheel arch liner, but that's been very helpful. Much easier to fix a good light in the arch and also a good opportunity to clean out the wing and apply a little fresh rust proofing. As for the fitting of the pads - I do agree it seems odd that they don't fit. However the slider plates etc. are very clean, possibly new, and as far as I can tell (I may not be an expert) there is no plate lift, whereas it is obvious on the old ones. The poor fitting could just be down to EBC not getting the pad size quite right? Has any one else bought any yellow stuff pads recently? Chris 87 Turbo.

 

[dunc]

Yeah I find yellows need the paint chipped off the edges to fit anytime I've used them. Think they start off the correct size before they are painted yellow. It's a reasonably thick coat. Dunc

 

[Diver944]

I'm swapping my road pads out for Yellows at the weekend (in readiness for Bedford) so I will let you know how easily mine fit

 

[amrbose14]

Forgot to (leave work and) go to the OPC to pick up bolts and washers for the calipers today (sigh)... I'll not start filing the pads until the caliper is mounted finally. Priorities... priorities...

 

[amrbose14]

I've been having comparing my old calipers with the replacement.... the pistons look quite different sizes. I gather there was a change in the dust boot style over time, but I'm surprised the pistons look so different. Is some of the piston on the later calipers hidden when they are depressed into the caliper? There are the old ones that came off the car...

 

[amrbose14]

And this is the new set...

 

[Diver944]

I may be wrong but looks to me like the new callipers have smaller pistons as if they were a set for the rear of the car [&:] What are the actual diameters of each piston?

 

[amrbose14]

ORIGINAL: Diver944 I may be wrong but looks to me like the new callipers have smaller pistons as if they were a set for the rear of the car [&:] What are the actual diameters of each piston?

I've not measured precisely, but they look like ~35-36mm and ~30mm, which does not seem to fit either the front measurements that litter the internet (36 & 40mm) or the rear (28/30mm). Which begs the question what they came off. Supposedly the front of a 944 S2. There a little on rennlist about early vs. late calipers, but it still doesn't seem to explain the apparently small size of the pistons I have, unless the piston is larger further in and the boot is hiding a further increase in diameter. http://forums.rennlist.com/rennforums/944-turbo-and-turbo-s-forum/661063-early-vs-late-brembo-caliper-pistons-whats-the-difference.html Having already had to swap around the pipes I'm not feeling terribly lucky! Chris ------------------------------- disc/piston dimensions '86 951 F: 298x28mm rotors, 36/38mm calipers R: 299x24mm rotors, 28/30mm calipers '87-88 951, non-S F: 298x28mm rotors, 36/40mm calipers R: 299x24mm rotors, 28/30mm calipers '88-91 951, Turbo-S/SE F: 304x32mm rotors, 36/44mm calipers R: 299x24mm rotors, 28/30mm calipers