Big Brake Upgrade

a2sumo said:
hmm... mike spongy pedal??? could it be those "iffy" titanium pistons?
Click to expand...

Very much doubt it Mike - unless the drill hole that wasn't set properly has just about gone through and is porous?

Failing that, the dimensions were/are spot on, so there won't be any weeping past the seals.

I'm not too sure of the new braided lines to be honest, nor the stainless bleed nipples.

I'll leave it a few days and hope it keeps dry then check for leaks and weeps.

Cheers,

Mike
 
"unless the drill hole that wasn't set properly has just about gone through and is porous?"


i very much doubt it mike as im sure i checked it out-i think the wall thickness was still 4mm ish- BUT if it is a problem just let me know. i do know that the abs pumps on some cars are a royal pain in the rear to bleed out. i know you havent opened the system up that high but any leakeage at the hoses does chase back very quickly. i would have thought if it was the hoses or blead screws you would have seen some fluid by now. lets hope you sort it quickly---nearly as quick as your a2 will stop now!
 
Absolutely agree, although I didn't measure the wall thickness of that piston.

The worrying part is that the pedal will contine to go down if pressed hard. If there was just air in the system, it'd compress and the pedal would 'bounce', but this really does feel like a leak.

On;y time will tell really - fingers crossed for a few dry days until I get a chance to check it out at the weekend.

I wasn't in any way doubting your engineering skills by the way - if anything, the titanium pistons are the strongest link in the chain!

Cheers,

Mike
 
"I wasn't in any way doubting your engineering skills by the way - if anything, the titanium pistons are the strongest link in the chain!"

no problem mate i know what you meant straight away. i was gutted when i realised what had happened shame i ruffed the bore out on both first as i would have noticed it on the first one.
pedal going steadily to the floor does sound like a leak----so you should soon see fluid loss at the reservoir or damp parts at the caliper. if you take the caliper off again you can check to depth of the false cut with your digital caliper--use a steel rule or other flat surface and measuring down into the hole with the depth gauge part. then taking that measurement away from the overall length of the piston (minus the thickness of your flat surface). i made the pistons 58.5 mm long incase you have no records of the piston drawing.
i hope that makes sense!!!!! cheers mike
 
Hi Mike,

Not the same vehicle of course,but I had a new set of front disks and pads on my diesel van a few weeks ago and the pedal would go down to the floor if I kept pressing. It all came god after about 100 miles, hopefully the same applies!
 
Thanks for the reassurance from the other side if the world Daz, it could just be the pads bedding in I suppose - time will tell!

If I do disassemble the calipers again Mike, I'll do a depth test, but it should be pretty obvious if there is a pinpoint hole, as there'll be brake fluid inside the piston!

Cheers

Mike
 
A little yes, but it's still there - thing is though, you hardly have to press the pedal to stop the car now!

I tightened the drivers side caliper banjo bolt the other day and was a little concerned that I've on the point of stripping the threads!

Not done much mileage though - maybe 100 or so miles since the upgrade.

Cheers,

Mike
 
How did you bleed the system?

The master cylinder seal can be damaged if the pedal is pushed to the floor when bleeding the system the old shool way.
 
You could try this old fix for spongy brakes, as had simular problems with my xr2 many years ago, after upgrading all my brakes and just could not get all the air out of the system as brake pedal seemed spongy,
you need to press the brake pedal down hard and wedge it there overnight ( it forces any air in the system to the highest point, back to reservoir ), find a length of suitable timber say 3 to 4 foot long, slide the seat fully back and find a suitable location to wedge against , ie seat runner ect and measure distance to brake pedal pushed down hard and wedge it up and leave it overnight. 99% of the time this works but sometimes youl need to do a quick bleed as air has been forced to the caliper bleed nipples aswell as a highest point.

Goodluck

Regards

Gary
 
So, I know someone who has a pair of TT 3.2 V6 front discs and pads lying about. Do we think they will fit (340mm discs) and if so, do I just need TT hubs which are a direct swap for the A2 ones? Or does anyone know a list of bits required to do the swap? If the V6 items won't fit, what is the list of parts required from which TT for Skiptons conversion? Thank you for any input.
 
I can't answer your question but I do know where there's 2 TT's being broken up for spares and at least 1 of thems A Quattro and all the brakes and suspensions are still there on them both as had them in mind for my own 4x4 upgrade / conversion , I'd also be interested to know if the hubs are a direct replacement / upgrade and I could possibly pick u up the second set of front hubs if you need them Ricardo. regards Gary
 
I have emailed three breakers for quotes, including one in Norwich :) If the TT hub is a straight swap then it opens up LOTS of choice for brakes including Porsche calipers. Good luck with a quattro A2(!) I think the best option would be e-tron, with motors on the rear wheels. I would be interested in the price of the hubs, but amazed if they are a straight swap given strut diameter, suspension geometry, hole spacing, driveshaft spline size (90PS same as 250PS!!) etc etc
 
Just read through the German forum and via usual weird translation it appears the S3, TT and Golf hubs (312mm discs) do fit the A2 - although there appears to be one person questioning it. If anyone speaks fluent German it would be nice to have a good translation. Then I guess, the 3.2 calipers (TT V6 and R32) provide the option for the bigger discs (340mm).
 
Did you bother re applying the locking fluid to the drive shaft splines ? Or is this not nessary ......
 
personally I have never applied the loctite and never had a problem, my logic is I may want the shaft out of the hub again
 
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