HELP A few problems with replacing rear brake pads on original /6., Pins not fitting and trouble retracting pistons Options

[Mueller]

So I was helping Sandy with his original /6 yesterday , we put new Porterfield pads on his car.

Fronts are easy, however the rear I ended up putting the stock pads back on due to a few reasons:


Large diameter pins wouldn't fit into new pads, options:

Grind down pins or drill/mill the backing plate for larger diameter? Easy options, just not sure which is preferred.


The bigger problem was that when retracting pistons for new pads which are about 1/8" wider due to being new we started to leak a lot of fluid and I got nervous if something like a seal was being damaged while screwing out the outer allen key?



So, is it okay to keep turning the screw to make room for the new pads and then once the .008" clearance is achieved just tighten the 13mm nut with no more leaks?

[SirAndy]

I know nothing about stock rear brakes but i have always just pushed the pistons back by hand (or clamps if the pistons are sticky) when replacing brake pads.

Not sure why you would need to turn the adjuster if all you want is for the pistons to retract.
(IMG:style_emoticons/default/confused24.gif)

PS: Do *not* grind down the original /6 pad pins! They don't make them anymore ...

[Mueller]

I know nothing about stock rear brakes but i have always just pushed the pistons back by hand (or clamps if the pistons are sticky) when replacing brake pads.

Not sure why you would need to turn the adjuster if all you want is for the pistons to retract.
(IMG:style_emoticons/default/confused24.gif)

PS: Do *not* grind down the original /6 pad pins! They don't make them anymore ...

I was afraid of breaking something by squeezing the pistons back in.

So the adjusters are just for fine tuning the gap and I can manually push the pistons back into the bores without damaging anything?

I'll modify the brake pads instead of the pins!

Thanks.

[SirAndy]

So the adjusters are just for fine tuning the gap and I can manually push the pistons back into the bores without damaging anything?

Like i said, i know nothing about stock brakes ...
(IMG:style_emoticons/default/huh.gif)

[11tenths]

Those rear /6 adjusters can be troublesome- please read Eric's (PMB) articles on retracting the pistons, which are captured by the threaded adjusters. The outsides are easily accessed, the insides- not so much. An extension and socket through the trailing arm is neccesary, and you may even have to use an air power ratchet burst (IMG:style_emoticons/default/w00t.gif) to overcome the 'stiction' of a reluctant adjuster.

Please search for Eric Shea's description of this procedure, which is how I learned of it.

And remember the two adjusters work opposite each other for creating clearance.

Good luck. - Harry

[914Sixer]

11tenths is correct about moving pistons back. You will have to drill hole to make pin fit. Rear pads are used on lots of European cars.

[Luke M]

The pad/pin issue has been around for as long as I can recall.
You have to drill out the hole in the brake pads that take the larger pins.
Problem fixed that way. I've been doing it that way on 6's since the late 80's.
Then you adjust the pad drag on the calipers. Remove the adjustment covers, use an allen wrench to adjust pads , re-install caps and done.

[11tenths]

I believe this 36min video from PMB is where I learned of the rear adjuster's unique properties;

go to the list on the left side of Eric's site and click 'Videos", drop down to the second one.

Also Armando's terrific site;

http://www.pbase.com/9146gt/factory_origin...s_calipers_rear

Cheers- Harry

[sbsix]

Drill the pads to fit the pins. It works and it’s easy.

I had new rear brake pins turned out of stainless steel rod many years ago and they’re still in perfect condition. A friend did the job for me at his machine shop. The rods came from McMaster. I wish I could remember the diameter to tell you.

[ClayPerrine]

I also want to add something...

The venting clearance in the book is way too big. If you cut it in half to .004, you still get enough clearance for the brakes to function correctly, and the park brake works better.

[jcd914]

I also want to add something...

The venting clearance in the book is way too big. If you cut it in half to .004, you still get enough clearance for the brakes to function correctly, and the park brake works better.

(IMG:style_emoticons/default/agree.gif)

It is not unusual to leak some brake fluid while turning the adjusters to retract the pistons or even when just simply adjusting the venting clearance.

It should not continue to leak after you tighten the lock nut.

Jim
No

[Mueller]

I also want to add something...

The venting clearance in the book is way too big. If you cut it in half to .004, you still get enough clearance for the brakes to function correctly, and the park brake works better.

(IMG:style_emoticons/default/agree.gif)

It is not unusual to leak some brake fluid while turning the adjusters to retract the pistons or even when just simply adjusting the venting clearance.

It should not continue to leak after you tighten the lock nut.

Jim
No

Thanks all....


Will watch the video later on. Sandy ordered new rotors today...his current rotors didn't look that good, lots of embedded metal or something was just off on them.

Thanks.

[Amphicar770]

I had to use the air power burst on one if my stuck adjusters. Used a butterfly impact wrench. While 18v Milwaukee has replaced most if my air powered tools this required air. It's not about torque but rather the immediate burst of rpm.

[rgalla9146]

This is an interesting discussion.
In my experience if an adjuster didn't move a piston you could spin it at one RPM
or 9000 RPM and nothing happened. The clutch devise simply could not overcome the resistance of the piston to move.
When I had such a problem I would lever the piston in while turning the adjuster.
This would usually free the piston and allow pad installation and adjustment.
Flushing and bleeding afterward is a good idea.
I've never heard of using a power tool to turn the adjusters.

[Mueller]

Got passanger side rear brakes done.

No inside (near trailing arm) adjuster on drivers side inside caliper half

Piston does not want to go in...no way to screw it in or out..

[jcd914]

Got passanger side rear brakes done.

No inside (near trailing arm) adjuster on drivers side inside caliper half

Piston does not want to go in...no way to screw it in or out..

You can pull the adjuster from the passenger side caliper and use it to adjust the driver side caliper.
They tend to stick on the end of the allen used for adjustment and get lost.

I problably have an extra, I'll look.

Jim

[bdstone914]

Got passanger side rear brakes done.

No inside (near trailing arm) adjuster on drivers side inside caliper half

Piston does not want to go in...no way to screw it in or out..

You can pull the adjuster from the passenger side caliper and use it to adjust the driver side caliper.
They tend to stick on the end of the allen used for adjustment and get lost.

I problably have an extra, I'll look.

Jim

(IMG:style_emoticons/default/agree.gif) Good idea. But is it the inner out outer adjustment screw? One has an allan head and jam nut. The other has a replacable gear.

[jcd914]

Got passanger side rear brakes done.

No inside (near trailing arm) adjuster on drivers side inside caliper half

Piston does not want to go in...no way to screw it in or out..

You can pull the adjuster from the passenger side caliper and use it to adjust the driver side caliper.
They tend to stick on the end of the allen used for adjustment and get lost.

I problably have an extra, I'll look.

Jim

(IMG:style_emoticons/default/agree.gif) Good idea. But is it the inner out outer adjustment screw? One has an allan head and jam nut. The other has a replacable gear.

I took the "No inside (near trailing arm) adjuster" to mean the inside adjuster gear that has to be accessed through the trailing arm.
I was fairly common to have cars missing 1 or both, I used to keep a spare in my tool box to use as a tool.

Jim

[Mueller]

I was too beat to remove the adjuster gear from the good caliper so we just threw in the old pads on the drivers side, I know not ideal but it was a long day!