Skip to main content

It would appear that is the only place that still sells these older pads.

Any one else selling them???

Also, does anyone have a pic of the REAR GD535 pads handy? I have a Porterfield box with a new set of pads in them.....but am unsure if they are R4S's or stock replacements that got stuck back in the R4S box.......ugh! No numbers or writing of any sort on these new pads.


Original Post

Replies sorted oldest to newest

Porterfield will weld a round pin to the back of the pad. When I replaced my stock pads with the Porterfields they had forgotten to do it and I had to ship them back. The stock pads had a square or rectangular stub rather than the round pin. Also I had to file down the pin because it was too long and contacted the brake first.

If you have pads with no bumps, You can also just tack a quick blob of weld to the back of the pad. If you like, make a sharp edge with a grinder.

Put it high or low on the pad, not in the center.

The pin/protrusion is only to keep the piston from rotating. It' s not rocket science, and might save you a couple weeks, and shipping costs.

OK, got real lucky with first caliper teardown, all 4 pistons cleaned up nicely! Soaked them overnite in Evap-O-Rust and two came out bitchin, but other two are soaking again for some cleanup work....just aesthetic....useable as is but why not......!

Just tore down caliper #2 and I found one small piston is pitted about 1/4" from top of seal area. Not good. This is area that would be contacting seal when you put in new pads......

Anyone have a spare small (34mm) piston from previous rebuild that they could part with? Will gladly trade beans for a good piston!

Advise accordingly !!! Thanks in advance!

OK, I think Porterfield put me on as a field tester......

To recap....

The rear pads that came with my car didn't have the "Pantera pin" but I sent them back and they sent me a new set along with a new set of front pads!

Upon checking my front pads for fitment.....I discovered they sent me "unfinished" pads....the hole was not drilled for the locating pin! Sent them back and they promptly sent me a finished set.

Was assembling the one rear caliper that I could at the moment....and ran into the issue that was mentioned above, where "pin" must be filed.... To me, that is dangerous to ship pads that are "unfinished" like that!!! I got no paperwork saying that filing would be needed....and only noticed that it was mentioned above, right now!

The groove in the piston is about .075" deep. The pin is about .090" tall. That is a lot of wrong.....for the money IMHO.

If an unexperienced owner were to assemble the pads without shortening this pin, the potential for lots of bad is great..... wearing rotors unevenly.....gouging up the piston....pads walking in the calipers could wear them in a bad way.....

So, I advised the nice person that was helping me (Wendy) that this needs to be brought to the attention of their engineering group for changes.

I attempted to file the pin, but my files just walked over the top of the steel....perhaps they took on some hardness during the welding process...... So I used my air cutoff wheel and carefully ground them down to fit.

This could be a PITA for a customer....and why would Porterfield want to piss people off.....I'd want to sell more pads!

So, still searching for a good small front piston.......I know they are out there! Found some new ones too, but would be coming from UK, and there are still some dimensions!


Add Reply

Link copied to your clipboard.