UrS6 Broken pedal box + clutch master cylinder

[John.]

3 mm thick should do the trick !!!

[Michael S2]

Finally got round to tackling this today having ordered a right angled drill bit weeks ago from ebay. Turns out i didn't actually use it as it makes it even harder to drill the broken part.

First step was to get the broken part back into alignment. Ended up using a hammer and metal bar. It's not perfect but about as close as i can get it.

Then got a 3mm steel plate and drilled suitable holes.

Used a 35mm hole saw for the big hole for the master cylinder to go through. Then the 2 bolt holes (M8 i think) were drilled. These are 50mm apart over the centre of the bigger 35mm hole. Lots of taking off/on of the plate to make sure i was drilling correctly. I still got it a bit off and had to file the holes to make sure they lined up.

Next up was the hard(er) part. Access is very limited with the pedals in the way and everything else, the goal is to get a new hole in the good steel of the pedal box. I drilled a hole in the steel plate (off the car) and then bolted it in with the 2 existing holes so i could mark where i wanted to drill the new (3rd bolt) hole in the car. Wasn't much fun but i got there in the end. New m6 bolt and washers on and the plate feels rock solid.

In an ideal world i'd like the pedal box out and welded properly to strenghten it.

Tomorrows job is to adjust the clevis by 3mm and refit the master cylinder.

Will update as and when i can.



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[Michael S2]

Great tips once again Not had time to go near the car yet to bend it back into shape. At least it sounds do-able from Macspring and Newsh. It is thin steel i'm surprised it lasted 160k miles

Another point is on closer inspection i think my master cylinder is fine. Because the shaft was moving out of line with cylinder i thought it had broken. Didn't realise it was a ball fitment on the shaft so can move around which makes sense right enough. It goes into the cylinder with just hand pressure and returns itself.

So why i suddenly had no clutch remains a slight concern. I hope it's just that the broken pedal box bent so far that eventually it wouldn't function. If not, i hope i've not got another problem. Anyway sort pedal box and refit and go from there.

[newsh]

Agreed, it’s just him mild steel.
I would start with an adjustable spanner with a hefty screwdriver through the hole in the end of the handle. The adjustable can be set as quite a tight fit on the sheet steel. A few tweaks and twists and it’ll be straight.

[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.

[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]

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]

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

Sent you a private message

[b collins]

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

[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

[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.

[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 !!

[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

[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.

[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.