scoobyc

iTrader: (2)

aaaallso. This is more of a generic question for brake upgrades.

Should the pedal feel softer after a big brake upgrade because its having to shuv more fluid?

Currently my pedal feel on my 4 pots is perfect. Rock solid feeling and responsive and even braking (with the ds2500) atleast.

Should i expect more pedal movement for the same braking force?

stockcar

generally speaking you should have a better pedal with AP's..........

alyn

scoobyc

iTrader: (2)

By better you mean stiffer, more linear. They didnt feel wrong. Just a quick thought thats all.

172sport

iTrader: (6)

It all depends on the piston sizes relative to the std setup.

stockcar

as in it will have slightly less travel and be more responsive

alyn

scoobyc

iTrader: (2)

Ok Thanks.

Ian you got a price for the adapter/mount?

Thanks

Nolan_WRX

iTrader: (3)

Also suffered with massive amount of judder/vibration at one point, thought it was warped disks or pad deposits, took a chance and changed pads from the ds2500's to mintex 1155 and it seemed to cure it.

scoobyc

iTrader: (2)

I might give the set another go this weekend then. Then it would give me a week to put it through its paces and decide if its suitable for the weekend afters track event. Or atleast it will let me determine if they are warped or if it was excessive pad deposits. Getting through my brake fluid chaning calipers all the time! at 10.99 rbf600 aint cheap! Might just buy some 5.1 halfords and use that untill i got it sorted, then flush it through with the good stuff.

scoobyc

iTrader: (2)

bttt

172sport

iTrader: (6)

Never bothered using anything other than DOT 4 here.

No issues at all even with all the trackdays.

If it dont cause probs why change IMHO

Damn cheap too

scoobyc

iTrader: (2)

Didnt get time to try them on weekend as had repaires on sunday for the defender n disco after abingdon. Ahh well!

Looks like ill be running 4pots on saturday!

scoobyc

iTrader: (2)

Quick update.

Sanded the pads back and the disks. Have put them on the car. And the judder is Massivly reduced! However there is still a small amount of judder. Think ill run them for a week and see how i go. Or ill get them skimmed properly tomorrow. They do have a bit of a bronzy colour on the disk tho.

Also all pistons are moving freely.

jasonius

iTrader: (1)

One thing to watch out for with the CP5200 is the clearance between disc 'rim' and the spring pad plate. If it's too tight they can make contact when the disc becomes very hot and expands (in diameter). Looking at your pics you can see witness marks on the disc. I recon if you also look on the underside of the pad plate you'll see a corrisponding mark.

I had this on my full AP kit after fitting and it wasn't until Pete Collen at AP had a look that it was identified. He very kindly re-shimmed then for me FOC..

This problem really becomes evident if the disc's are allowed to rust up, through lack of use etc, as the rust tends to build up on the outer disc rim, effectively increasing it's diameter and compounding the issue..! If the rust build up is excessive (flaky looking) careful tapping with a hammer around the disc edge soon removes it..

I doubt that this is what is causing the 'judder' but does make a 'tishsss-tishsss-tisshss' noise when they're hot, which I think is what you refered to in your original post..?

One observation, you've measured the disc thickness as 29mm iirc..? The CP5200 takes a 28mm disc max..! Whats the diameter of the disc..?

If it's pad deposits that are causing the judder you need to effectively re bed the pads, not just give them a hammering. High speed- hard braking, without ABS kicking in down to 20mph, back up to speed and repeat several times. Run to cool for 5 mins and then repeat again. Have you tried roughing up the pad surface a little with some sand paper..?

Finally, google/email Godspeed and see if Ian can knock up some decent alloy brackets, as those you have do look terrible..

Cylon2007

"Also the caliper today had a stuck piston! Got it moving easily enough tho, extended it and cleaned it. Do i need to copper grease these pistons up?"

NEVER EVER EVER grease the pistons with Copperslip or any grease other than Red Rubber Brake grease or something specifically designed to work safely with the seals in brakes.

Copperslip should only ever be applied in a very thin layer to the back of the pad where it sits on the face of the piston and the edges of the pad where is slides in the caliper.

From the pictures I would say that caliper has previously had stuck pistons and the damage showing on the edges of the pistons would have been caused by using brute force to remove them.
I would NOT use those on any car of mine. Go back to the seller and demand your money back.

scoobyc

iTrader: (2)

Cheers jasonius. Yeah looks like thats the case. Nothing a little bit of maching wont fix.

The one sticky piston free'ed up fairly easily.

Disks are getting skimmed. I will asses after that whether ill keep it with a godspeed alloy bracket.

Yes not very good purchase. money back isnt an option.

jasonius

iTrader: (1)

Lol, had to 'de-rust' mine again recently after the car sitting around for a few weeks unused.

The main problem with mine is they don't really get used hard enough often enough..!

The other thing (with a lot of AP calipers it seems) is the inner bleed nipple often becomes very tight/seized. So if you have the opportunity take them out and put a smear of Never Seez on them before refitting. I'd like to do mine, but with braided ss hoses it gets very messy with fluid 'burning' the finnish off your lovely expensive calipers..!

Would it be worth getting some new pistons off Ian too..?

If your stuck with them you might as well do it properly..

scoobyc

iTrader: (2)

Yeah we shall see what the skimming brings.

if that can sort it, i can then go and buy everything i need to refurb them and a new set of pads should i wish still for less than they cost new. But if i need new disks then it will have been a false economy.

to be fair the pads look fine. The disks look like new, the calipers them selves are in decent condition, everything is aligned and fits with no bangs evident and they seem to operate. Its just the pistons look a bit scored where someone has had them out.

The caliper adapter is very sturdy, just the ground off bolts are a bit suspect, however they seem to not be too structurally compromised. But still a concern.

Fingers crosses the disks come back well and everything ends up perfect.

Do we know if ASP disks are the same offset etc as Ian's disks? If they are then should be ok to get one of his proper brackets.

jasonius

iTrader: (1)

If they're AS Performance (ASP) disk's asking Alyn himself would be best bet. He's a sound bloke and posts as 'stockcar' on here, so you could PM him..

stockcar

i think he means AP discs???

the discs will have exactly the same fitment generally, its the bell that dictates the exact position

alyn

jasonius

iTrader: (1)

There you go, i said was helpful..

Hi Alyn..

stockcar

hello...............LOL

scoobyc

iTrader: (2)

Ahhaa hello Alyn,

yes i mean ASP. person i bought them off recommended you if i ever needed new disks. And as these looks pretty much new, the disk atleast i was hoping you would have supplied him.

From the pcitures does the bell look familiar? As its gonna be the size/offset of the bell which is going to determine the bracket size/shape assuming all 5200's are the same caliper dimensions. I.e. if i can determine these bells n disks are pretty much the same as any other for this caliper, i can go for one of ians adapters without him having to machine a new one up...

disks still at the shop. hopefully have um back on today to find out more..

stockcar

we do various discs from various suppliers, but it would depend on the number of bolts holding the discs to the bell and also the PCD of the bell.............

even then if the bells and brackets have been made as "one-offs" then its no guaranteed that another bell and bracket would fit correctly as a simple swap

alyn

scoobyc

iTrader: (2)

Right. Its a bit late but quick update.

Got the disks back today and fitted them up, and hey presto. No judder at all! The brakes feel really solid now ive bled them a few times properly. Only been for a quick ten min spin, but initial results are good! Will use em for work for a couple of days and just monitor them closely.

100 million % improvement from when i first put them on. for the first time they actually feel like good brakes!

Will get em off on the weekend again and inspect everything properly and check the stiicking piston is now free.

Cheers for the advice guys!

scoobyc

iTrader: (2)

Ok another quick update.

Brakes were superb on drive to work this morning. normal braking with a couple of higher speed and hard stops. Brake pedal feels solid.

If anything id say perhaps the bias has shifted to the front, any ways to check brake bias? Of course it could all be in my head...

jasonius

iTrader: (1)

Glad to hear you've got them working properly..

Lol, the rear bias is fixed (unless you fitr a manual bias valve, which IMHO is a no no for a road car..!). A few things may help, such as better rear pads and better suspension.

Try pads first..lol as this is where you head towards that very slippery slope know as impreza modifying..

scoobyc

iTrader: (2)

Yeah the rears already on ds2500's and suspension is already upgraded. Done a few braking tests and i rekon its probably in my head. Yet to give them a kickin tho.

Lets hope they are a marked improvement on track.

so much left to buy for this bloody thing!

scoobyc

iTrader: (2)

Hmm the judder is back. Happens at super high speed or if i get them very very hot.

Also when parked up after a burn i can hear a very loud and distinct cracking noise. Is this the contracting disk on the bell. is this a normal sound? No cracks visible..

Ian any idea if your mounts would be suitable for these disks? You have email.

Cheers
Chris

scoobyc

iTrader: (2)

also looks on the spec sheet they can take 32mm disc max. disc centralisation has to be within 0.5mm


Ian can you please let me know the dimensions of your Bells, Disks, and mounting brackets so i can see if anything is compatible...

Thanks
Chris

jasonius

iTrader: (1)

Have you checked for flaky rust on the outer edge of the disc..? With all the rain we've had recently, unless the car has been regularly driven hard, enough to burn off any moisture this is a strong possibility..

This effectively increases the diameter of the disc and therefore rubs the cp5200 caliper pad plate..