Problem on S2/Turbo brakes
02-18-2002, 11:19 AM
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Problem on S2/Turbo brakes
Just figured out why my brakes do not work reliable.
Problem are the "leading frames" for the brake pads.
The alluminium of the caliper get oxidated and lifts the "leading frames" and the the brake pads get stuck intermittantly.
Depending on brake pressure and wheather. <img src="graemlins/burnout.gif" border="0" alt="[burnout]" />
My question:
Did anyone rebuilt these chromated "leading frames" ?
What needs to be done to get the two M4-screw out of the caliper ?
They are totally stucked and there seems no other way than to drill them out. <img src="graemlins/crying.gif" border="0" alt="[crying]" /> <img src="graemlins/crying.gif" border="0" alt="[crying]" />
Problem are the "leading frames" for the brake pads.
The alluminium of the caliper get oxidated and lifts the "leading frames" and the the brake pads get stuck intermittantly.
Depending on brake pressure and wheather. <img src="graemlins/burnout.gif" border="0" alt="[burnout]" />
My question:
Did anyone rebuilt these chromated "leading frames" ?
What needs to be done to get the two M4-screw out of the caliper ?
They are totally stucked and there seems no other way than to drill them out. <img src="graemlins/crying.gif" border="0" alt="[crying]" /> <img src="graemlins/crying.gif" border="0" alt="[crying]" />
02-18-2002, 07:55 PM
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Yup, removing and cleaning under that plate is supposed to be a routine maintenance item! You can remove those M4 bolts by using an air impact chisel and getting it to bite onto the surface of the bolt head. You can then use the impacts to turn it counter-clockwise. That is, you have it bite into the edge of the bolt and use the bolt head to leverage the bolt out. It's a pain, but it can be done!
Good luck!
Dal.
Good luck!
Dal.
02-19-2002, 03:40 PM
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it is possible. 've done this on all four onmy car and they were 13 years old.
Don't forget to buy new parts from porsche and aply some Cu paste there. (or leave them out as many do)
Konstantin
Don't forget to buy new parts from porsche and aply some Cu paste there. (or leave them out as many do)
Konstantin
02-19-2002, 04:13 PM
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I've just had the same problem with my '91 944S2, I had to take the calipers to work and I got one of our welders to TIG weld an M6 nut to the top of the screw and then it came out quite easily, I think it was down to the better grip you get with a nut as opposed to and allen key and the fact that it had been heated up. I also found that when I had cleaned all the corrosion and oxidation from behind the steel plates and put every thing back together, the brakes squealed really badly. I think this could be caused by the fact that in removing the oxidation and getting back to good sound aluminium, the steel plates have nothing behind them when they are bolted in place and when you apply the brakes they are vibrating at a high frequency and causing the squealing. Anybody got any comments on this theory?
I have considered stripping the brakes down again and putting some "chemical metal" ( a product available in England that is like car body filler, you mix it up and it is supposed to set like steel ) behind the stell plates so that they are held in palce firmly and cannot vibrate, the only thing putting me off doing this is the temperature that chemical metal will withstand, I'm not sure it's high enough.
If anybody has any ideas on how to stop this squealing I would like to hear them.
P.S. I did use plenty of copper grease which stops then squealing for a while put it's not long term.
<img src="confused.gif" border="0">
I have considered stripping the brakes down again and putting some "chemical metal" ( a product available in England that is like car body filler, you mix it up and it is supposed to set like steel ) behind the stell plates so that they are held in palce firmly and cannot vibrate, the only thing putting me off doing this is the temperature that chemical metal will withstand, I'm not sure it's high enough.
If anybody has any ideas on how to stop this squealing I would like to hear them.
P.S. I did use plenty of copper grease which stops then squealing for a while put it's not long term.
<img src="confused.gif" border="0">
02-20-2002, 06:41 AM
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@AndyS2,
did you tile the calipers before welding the M6 nut ?
Do you remember whether the caliper gets (too) warm with regards to the rubber gaskets ?
At least it sounds that the caliper doesn't need to be disconnected from the brake lines.
BTW For the moment I have abraded my brake pads accordingly.
@ Konstantin,
why replace the spring pads ?
They look like brandnew and after cleaning, without any corrosion.
did you tile the calipers before welding the M6 nut ?
Do you remember whether the caliper gets (too) warm with regards to the rubber gaskets ?
At least it sounds that the caliper doesn't need to be disconnected from the brake lines.
BTW For the moment I have abraded my brake pads accordingly.
@ Konstantin,
why replace the spring pads ?
They look like brandnew and after cleaning, without any corrosion.
03-03-2002, 06:10 PM
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Prospeed (a Rennlist sponsor) <a href="http://prospeedmotorsport.com/index.htm" target="_blank">http://prospeedmotorsport.com/index.htm</a> rebuilds and powder coats calipers. Price varies if you send you old calipers in. THe pictures look good. I haven't used him myself, as I have other issues to address (like the camchain tensioner).
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03-04-2002, 01:18 PM
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[quote]Originally posted by Andy S2:
I've just had the same problem with my '91 944S2, I had to take the calipers to work and I got one of our welders to TIG weld an M6 nut to the top of the screw and then it came out quite easily<hr></blockquote>The screws are installed with thread locker. Porsche says to heat them up to 150 C with a hot air gun prior to removal. The backing plates are part of the repair kit and are considered a wear item. Use Locktite 270 for installation.
I've just had the same problem with my '91 944S2, I had to take the calipers to work and I got one of our welders to TIG weld an M6 nut to the top of the screw and then it came out quite easily<hr></blockquote>The screws are installed with thread locker. Porsche says to heat them up to 150 C with a hot air gun prior to removal. The backing plates are part of the repair kit and are considered a wear item. Use Locktite 270 for installation.