UrS6 Broken pedal box + clutch master cylinder

[Michael S2]

Folowing on from this thread...

https://www.s2forum.com/forum/technical/transmission/84462-urs6-failing-clutch-symptoms/page3

So my worst fear was realised after removing the plastic trim to gain better access to remove the clutch master cylinder. One cracked pedal box

Quick recap of how this happened....
Went to change gear as normal and heard a crack/pop and felt strange movement in pedal. At this point the clutch pedal only returned about halfway and bite point of clutch was near the floor. So i thought i'll need to get that looked at, but car was still driving fine for the next few days. Until gear changes became difficult to the point where i had no clutch pedal as it was on the floor. Changing gears with no clutch is doable but then i had to stop at a junction...game over . Flat bed recovery job home.

Was hoping it was just the master cylinder but on closer insection the pedal box is cracked. So the initial cracking sound will have been the pedal box going. After that the extra stress on the master cylinder means it was inevitable this would break.

So if you feel like something has broken get it parked up asap or you will just break the master cylinder or something else. I learned this the hard way. Some will say a clutch change could have prevented this, but my pedal was not particularly hard to press. So i'd say it's just luck if your pedal box is going to break.

Some photos attached. Is this fixable in place? At this moment i have no idea who i can get to fix this.

[John.]

I would say if you can find a "flexible welder" then it would save you time on removing the pedal box. By "flexible welder" I mean someone like yourself who will physically be able to lie on his back and get in there with a mig welding torch.
Have a word with a friendly blacksmith, at worst take out the box and get them to weld it up. Having it repaired will likely make it stronger than before?............obviously the importance of it being welded in the right place is paramount !

[Nuvo]

Shaun on here is breaking a UrS6, he might have a serviceable pedal bracket you could use.

[John.]

Shaun on here is breaking a UrS6, he might have a serviceable pedal bracket you could use.

Weld it/strengthen it before you fit it !

[Michael S2]

Thanks removing the pedal box would be ideal, but i'm sure i read somewhere that the steering column has to be removed to get it out the car along with loads of other bits (dash probably)? I really don't fancy this at all but it might come to it. Can anyone confirm this?

Otherwise i'm going to have get someone to heat it to get it back in the "correct" position then weld it with a strengthening plate of some sort.

[Vorsprung durch Technik]

That's a shame Michael. You'll probably remember the professor mentioning this in old threads. I'm sure when Dave sees this he'll have his finger on the button to provide you the info you need.

[Error404]

Not sure if it helps or is in any way relevant but I removed and refitted the pedal box on my coupe without removing the dash or steering column. It was a fiddle but not too bad, with any luck it’s doable on the C4

[John.]

.....heat it to get it back in the "correct" position then weld it with a strengthening plate of some sort.

Looking at your pictures could you not get a repair plate with holes in the right places and bolt it in, this would then pull the broken metalwork back into position? It could then be welded.
If it's looking possible I would definitely remove the seat and cover the carpe at least !!

[Michael S2]

Not sure if it helps or is in any way relevant but I removed and refitted the pedal box on my coupe without removing the dash or steering column. It was a fiddle but not too bad, with any luck it’s doable on the C4

Looking at your pictures could you not get a repair plate with holes in the right places and bolt it in, this would then pull the broken metalwork back into position? It could then be welded.
If it's looking possible I would definitely remove the seat and cover the carpe at least !!

I will have a better look to see if it's possible to remove the pedal box without removing everything else. Are there any photos of the pedal box out of the car? Would give me a better idea of what's joined where.

Something along those lines John might work indeed. If i got a square piece of steel with holes in the right place slotted it up behind where it's snapped. Then the tricky bit is securing it (maybe with a jubilee clip temporarily around some of the good metal in there). Then i could try and get a bolt tightened up through to bring it back into place.

[Error404]

If it were me I'd just bite the bullet & take it out & repair / replace it. Sounds like a pain in the *** whichever way you look at it

[b collins]

think i have a pedal box for s6 in the loft let me know if you need one

[Michael S2]

think i have a pedal box for s6 in the loft let me know if you need one

Sent you a private message

[macspring]

Couple of points to keep in mind.

1. It's a weak design by Audi of the RHD UrS6 pedal box.

2. A heavy / old clutch speeds up the failure of the RHD pedal box.

3. It's a pita to fix in position or take out and fix.

4. Anyone who has a RHS S6 should change the clutch if it's heavy, a new oem spec Sachs clutch is lovely and light as an extra bonus.

5. Anyone with RHS S6 should definitely take out the master cylinder and put in a metal gasket as per the outline in the Third photo posted by Michael before the pedal box fails and you're stranded.

6. Once you've made the metal 'gasket' plate one needs to drill an extra hole in 11 O'Clock position in the plate and a smaller hole down at the 5 O'Clock position while still allowing from the shoulders of the master cylinder to it. The two new holes should have a nut and bolt fitted to each and it will repair the cracked plate fault. It is pretty fiddly to do - the drilling ina confined space and stopping the nuts that are hare to access to hold from spinning as one tightens the two new bolts.

7. # 6 is still way better than taking out the pedal box or welding it in position. Being creative, and patient, together with the ability to curse profusely helps greatly.

8. If someone made up a metal gasket plate and sold it predrilled and ready to fit as an almost - in so far as it can be - plug and play repair they could sell them at a good price, because it is a faff to fix from scratch yourself, but the metal plate is the 'easier' fix imho whether you do it yourself or pay to have someone do it for you.

Best wishes.

[Michael S2]

Brilliant post Macspring . Starting to make sense of the gasket idea as it avoids 1. Welding in car 2. Taking pedal box out of car.

Drilling in place is obviously not ideal by any stretch but sounds feasable.

Will try and take some good photos of the gasket to help others as and when I get one made.

Now the only problem here is getting the broken piece back in alignment before I can begin to get a gasket bolted up. From memory it's a good inch out of line at the widest point.

I could try using some sort of clamp but i fear some heat might need to be involved.

[macspring]

Ironically I think the metal that the pedal box is made of is not thick enough to warrant heat to bend the broken part of the pedal box back into shape. A vice-grips and or suitably sized G clamps should help you to bend the broken part of the pedal box back into position.