Movit discs on RS4 (problems) solved by AP Racing. Discuss

[Jani]

Will do, but they do look similar in the testing pictures. I think the change is in disc "flange" thickness and vane design.

[flashyg]

Does this sound similar to you Dave?
Thanks for posting Jani,
Thankfully we are not waiting on these any more.
Looking forward to your testing.
If you get fed up waiting these are available.

G

[Jani]

Digging out the old post. I promised some pics, here the new versus old design: http://picasaweb.google.fi/jpeltopuro/Movit_370

The flange thickness and vane design do seem different. Can't comment on impressions though. The 4 is now with a new owner, and I'm with a 6 plus

[Tomson]

Christ.. I am still wishing I had never searched for 'movit' in the forums!!

Please can one of you guys help me out with a solution for my problem.

As you may, or may not know I bought JR's suspension and brakes a couple of years back. We did a straight swop at QST prior to him moving his car on for the porsche.

Anyway I believe this means I have the Movit 4 pot (GT2 Derived) 380mm kit?

On the way back from QST I noticed that there was some vibration under heavy braking although they were a relative 2nd hand bargain and so much better than standard that I really did not give a <beep>.

Anyway they have been steadily getting worse and on a recent trip to france any braking whether hard or soft causes passengers in the car to grab for the 'jesus' handles and nearly knocks my foot off the middle pedal.

I need to get it sorted.

The rears are also Movits and I know I need new discs there also. However to the eye the fronts look fine ( I think JR had them replaced by Movit?, although he did his fair share of track work) there is also plenty of brake pad still on the fronts. Again I beleieve JR used some ridiculous Carbon porsche brakes and thus far I have had not had to change them.

I have done about 12-15k on his 2nd hand set up.

So can someone please advise me on what I should do. I am happy to take it to my local garage, they are top lads although much head scratching will begin and I will be charged top $ for the solution.

Scrap the movits and go RS6+or B7 RS4 set up?

Replace front and rear discs with the AP solutions?

Take the multi dremel to the floor pn and go for the flintstones gig?

Thanks in advance for your help.

BTW I need to sort this ASAP.

[DaveP]

Hey matey....

There could be a few things causing your juddering...

Wheel bearings - although if they are really bad you should feel them in corners too.


Discs at end of life - you should really try to measure the disc thickness to find this out...but you may well be able to feel a 'lip' on the disc at the top and/or bottom of the pad. If the disc is too worn, it'll be too thin to cope with the heat you are generating when braking and will give you vibration.

Pad deposits - quite possibly... this can usually be cured by re-bedding in the pads by performing several high speed, hard braking (100-40mph - don't stop!) stops.... do 3 of those as quick as you can on a nice empty road.

The 380 / 4 pot Movit system didn't have the same problems as the 6-pot /370 solution (which was supposed to be better). They did grumble a bit when used hard on track, but always seemed to recover ok.

If it's discs...I have one spare 380mm disc (pretty much brand new) in the garage, Gordon might still have one lying around too somewhere... that would give you a new set of fronts.

I'll be surprised if the rears are anywhere near end of life...

[tdiquattro]

I have bad vibration from the 322mm Movit fronts, but only from high speed braking, these are with new discs and I am about to change the pads, I honestly think it's the wheel bearings which should be here from germany next week so I will let you know if that clears it up.

I also have the old Movit fast road pads in there at the moment, which I don't like, they score the discs quite badly and may be something to do with this vibration / pad deposits, anyway the new pads will be genuine porsche / Textar, which I ran before and they were much kinder to the discs and better in traffic.

[Tomson]

Thanks for your help guys.

Dave I might PM you about the spare disc.

There is no lip on the front discs and I was suprised at what great shape they actually looked in!

tdiquattro - please let me know how well you get on with the wheel bearings.

Finally - I will nip to my private road and try a few high speed stops to see if that helps.

I will report back with findings soon.

Cheers again,

T

[flashyg]

Yes the Race Spec Pads are a bit tricky.
I used them and had bad vibrations.

I gave all my discs to Gavin as he was desperate for 380's so I have none left.

Try changing pads £50ish for a set from a dealer.
G

[Tomson]

Right nipped over to hereford today in the beast.

Did some stpid braking all of the way there and it seemed to help a little. Also re-checked the discs and pads and everything looked a-OK.

I think I will gets the pads changed and give the front discs a cheeky little clean, quite a build up of <beep> in the vent holes on the discs.

What pads do I need to buy for the Movit 380mm 4-pot kit?
Also what type do people generally recommend?

Thanks again,

Tom

[tdiquattro]

Ok, here we go..

- I had the wheel bearings changed - no difference.
- Had the discs skimmed, and both had low sections, ie, the pads had taken a chunk out of the discs and caused a lower area on one side, I had exactly the same thing on the last discs with these pads, they are too hard/abrasive. The pads are Movit sport and are actually Textar 4045.
I have replaces them with genuine porche 993TT pads which are actually Textar 4040. Much better.

- On re-fitting it was clear that the discs did not always center correctly on the hub. The fault is with the Movit Alloy disc carrier in the center of the disc. The hub center on the S4 is 68mm (actually 67.8mm!) and the center of the standard Movit carriers is at least 1 or 2 mm bigger and is bevelled so that it doesnt push on but sits there loose, rubbish design. So the fantastic machine shop I use cut the centre out of the carrier and machined a push fit new centre with a 67.7mm ID, you should see the accuracy!.

So to sum up..

Movit pads are too hard/aggressive, the discs get low spots in them which causes the vibration.
The Movit carriers do not center the discs which causes them to run in and out.

Hope this helps, no vibration now, but I have not tried any aggressive braking as Im bedding them in.

Nigel.

[flashyg]

Thanks for the info. I found the centres to be an issue also.

[tdiquattro]

No trouble, some heavy braking since then, no problems at all, well chuffed, and apart from the pads the work only cost 30 euros!, bargain.

[johnRS4]

Thanks for the info. I found the centres to be an issue also.

Do it

John

[JohnW]

eh ?

do what John...

I too have the 380mm movit 4 pots, and they do vibrate a bit, but most of the time I find its the wheels or tyres are the problem.
I've used a set of porsche race/track pads before, and they grip like a b@stard, but really eat the disks, so I now use standard Porsche GT3 mk1 pads.

[Tomson]

Still not got around to sorting my issues out as yet..... not enough time. However I am going to try cleaning the discs up and changing the pads 1st.

John, I might also try changing to my BBS wheels as I am currently using standard rims and they do have a history of buckling. It will be interesting to see if this helps, one would suggest that if it is a brake issue it will be worse with the larger radius of the 19's.

I will also have a look at how they centre on the hubs.

Cheers all

Tom