Dragging clutch issue

[francisluu]

Hi everyone! First post here so please be gentle

I picked up a B7 RS4 late last year, almost 60,000 miles and with the original clutch. Engagement point was towards the middle of the pedal travel.

During a bit of maintenance a month ago, we had the clutch slave cylinder and clutch/flywheel assembly replaced, all OEM from JH Motorsports. Car felt great. Clutch engagement point was the same, right near the middle of the pedal travel. Over the course of a week and half, the engagement point creeps down towards the floor and it's starting to get difficult changing gears, a ton of resistance getting into first gear from a stop. The car even creeps forward while in first gear *and* with the clutch in as I bring the revs to 4000 RPM. Seems to me the clutch isn't disengaging all the way. So to recap briefly — new clutch/flywheel, new slave cylinder, started out great/normal, got worse. Again, all OEM.

First thing we tried was to re-bleed the system. No dice. Second thing was to replace the slave cylinder with a metal kit from USP Motorsports. Just got the car back from that and while it's no longer consistently difficult to get into first gear (on occasion there's some resistance), the engagement point is still almost right at the floor. It's risen maybe two millimeters. The car will still creep forward when in first gear, clutch is in, and I rev above 4000 RPM. It, again, isn't fully disengaging. To recap this particular trip to the Shop — didn't get better, didn't get worse.

I think we're hoping to try the master cylinder next, though I'm unsure if we can discount this being a mechanical issue with the clutch/flywheel install rather than something in the hydraulic system? Doing a bit more research before dropping the car off at the Shop again and would love some thoughts on this.

Height of throwout bearing being different with this replacement kit? Could it actually be the master cylinder? It just feels strange that new parts could cause the master cylinder (untouched in all of this) to fail. And again, it started off feeling great after the first visit to the Shop and we've almost definitively ruled out a leak in the system (unless of course it *is* at the master cylinder).

Thanks everyone.

[DavidRS4]

It’ll be the clutch pipe. Well known fault. Contact Robnic on here and order a braided one. It’ll be problem solved.

[francisluu]

It’ll be the clutch pipe. Well known fault. Contact Robnic on here and order a braided one. It’ll be problem solved.

Thank you! I haven't been experiencing issues with the clutch pedal returning or being stuck to the floor which seems to be a big indicator of the clutch return pipe issue. Does a faulty return pipe cause other issues as well? Pardon my ignorance.

[rs user]

as well as the pipe check the bellhousing bolts havent come loose a bit...it happens-same symptoms

[DavidRS4]

I’d just do the pipe to rule it out.

[francisluu]

Looks like the USP metal slave and hydraulic line conversion kit (https://www.uspmotorsports.com/Drivetra ... rsion.html) that we installed on the car already replaces the clutch return pipe that robnic makes a replacement for. I'm in the United States and his works for RHD cars only which need a shorter line.

Well, looks like we'll be trying the master cylinder next...

[Robnic]

Hi Francis,

Ok sorry I'm a little late to the party, yes the pipe I supply is only for RHD cars the LHD one is longer.

Here's my take on this;

Probability wise it could be the master cylinder - the clutch bite point was the same midway point after you had the new clutch & fly fitted, obviously once built up it needed bleeding, this involves 'over stroking' the master cylinder from it's normal point of travel i.e. pumping all the way to the end of it's stroke (to the floor) which can cause seal integrity issues - unless of course you fully pressure bled it and didn't over stroke it to the floor?

Other points to consider / check;

Slave cylinder (I know it's new) is leaking, peel the dust cover back and check, there should be no fluid, this I think is unlikely as you would have to loose a bit of fluid to suffer the lower biting point and you don't mention any fluid loss. The master cylinder can suffer air ingress giving a spongy pedal feel and consequently there is not enough 'solid fluid' movement to fully disengage the clutch, it should be noted a master cylinder can also leak fluid past the seal but back into the resevoir so you wouldn't notice any level drop.

Clutch - you say OEM, they are of a SAC variety (Self Adjusting Clutch) and should be fully compressed with a special tool, so once bolted to the flywheel the clutch disc will turn freely then the tool released to allow the clutch cover to clamp the plate - now a lot of peeps will be shouting they didn't do this and haven't had any problems, that is quite true but text book way is to fully compress the cover when fitting, but as said it can be fitted without doing this and not suffer any adverse consequences. See picture of the tool.

Bellhousing components - the clutch release lever and it's fulcrum (plastic pivot) are an updated part from O.E. fitment and as such should ideally be replaced when the box is out, also the guide tube (or retainer) that the thrust or release bearing slides on. All these parts are only 60 Great British Pounds or thereabouts.

Also as mentioned fitting issues including clutch cover bolts or bell housing bolts left loose!

Hth and you get it sorted bud
Cheers
Rob

[Covkiller]

I feel your pain. I had a nightmare with my clutch when I first bought my current RS4 with 54k on it. I replaced the lot and through Audi too, £3.5k, clutch, fly wheel, slave cylinder, hydraulic pipe you name it. Did a couple of k miles and the clutch died, same issue, bite right at the bottom and extremely hard to engage 1st. I took it back to Audi and they replaced the clutch plate and thrust bearing under fitment warranty. I'm still on the same one now 4 years later.

I also had a clutch fail on my 1st RS4 too after a new fitment, this too was replaced by Audi under warranty. Suffice to say, clutches fail even on low miles after fitting. It was funny when I rang Audi to say the clutch had failed, a young lady asked me, 'how do you know it's your clutch", I was so tempted to say, please put me through to someone with a brain.

Suffice to say, clutch problems on an RS4 B7 can be a nightmare and a guessing game. I hope you get yours sorted with the least amount of hassle.

[Robnic]

It wouldn't surprise me if they didn't clamp it before fitting the clutch cover!

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[RS4JAY]

Gents, looks like I am having the same issues?

Just yesterday, my RS4 started having problems engaging gear, the clutch, flywheel and all associated parts were changed a only a few thousand miles ago, in addition, the slave and all of robnic’s uprated parts were fitted. Up until this time the car was driving great, no clutch/gearbox issues whatsoever.

Yesterday, driving through city traffic at approx. 20mph, I was shifting in to 3rd gear and the gear grinded a bit, I thought nothing of it and put it down to the car being cold and me having a bad gear shift moment!!
Car seemed fine, drove a few more miles to my meeting, never though anything else of it. Couple of hours later, I left the meeting to drive to the office and the car gradually got worse over the space of 7 miles, to the point it will not engage gear now, or is very very difficult to engage.

If I fully press the clutch pedal to the floor, the car will still pull away. When in gear and driving, there is no slipping or issues whatsoever, it is only when shifting gear. Sometimes if I give it, some revs between changing it will select a gear.
The cars home now, but if anyone can advise of the potential issue before I start buying parts and throwing money at the car, it would be much apprenticed.

Thanks

[Robnic]

Difficult to diagnose without looking but does it feel any different the pedal pressure or is the pedal lower?
I would check first for any leaks around the slave, pipework and inside the car rod out of the master cylinder connected to the pedal, hth.

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[RS4JAY]

Yeah I know Rob, be a hundred guesses.

The clutch pedal originally felt fine, but by the time I got the car home, it did feel a little off, maybe a little loss of pressure at the first 50% of pedal travel, but not a massive amount. However the pedal does not sit any lower.

Difficult to diagnose without looking but does it feel any different the pedal pressure or is the pedal lower?
I would check first for any leaks around the slave, pipework and inside the car rod out of the master cylinder connected to the pedal, hth.

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[lengster1]

Clutch pressure plate fingers fail internally and sit high compared to others, i did the pipe etc etc on my old one but the pressure plate and friction plate are basically 2.0 tdi items and arent up to it

[lengster1]

The higher fingers push the release bearing back and the pedal throw is easy for first bit as its only pressing the few hight sitting levers

[RS4JAY]

The higher fingers push the release bearing back and the pedal throw is easy for first bit as its only pressing the few high sitting levers

So even though it is a new clutch this happens?

So basically i need an unrated clutch ?? I fitted a standard LUK clutch.

Rob, have you seen this before also?