HELP A few problems with replacing rear brake pads on original /6., Pins not fitting and trouble retracting pistons |
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HELP A few problems with replacing rear brake pads on original /6., Pins not fitting and trouble retracting pistons |
Mueller |
Jun 25 2018, 02:31 PM
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#1
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914 Freak! Group: Members Posts: 17,150 Joined: 4-January 03 From: Antioch, CA Member No.: 87 Region Association: None |
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 |
Jun 25 2018, 02:35 PM
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#2
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Resident German Group: Admin Posts: 41,815 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
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 |
Jun 25 2018, 02:39 PM
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#3
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914 Freak! Group: Members Posts: 17,150 Joined: 4-January 03 From: Antioch, CA Member No.: 87 Region Association: None |
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 |
Jun 25 2018, 02:46 PM
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#4
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Resident German Group: Admin Posts: 41,815 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
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 |
Jun 25 2018, 03:09 PM
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#5
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Ve get too soon old, und too late schmart Group: Members Posts: 142 Joined: 11-October 12 From: Islip, Long Island, NY Member No.: 15,026 Region Association: North East States |
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 |
Jun 25 2018, 03:15 PM
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#6
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914 Guru Group: Members Posts: 8,989 Joined: 17-January 05 From: San Angelo Texas Member No.: 3,457 Region Association: Southwest Region |
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.
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Luke M |
Jun 25 2018, 03:22 PM
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#7
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Senior Member Group: Members Posts: 1,389 Joined: 8-February 05 From: WNY Member No.: 3,574 Region Association: North East States |
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 |
Jun 25 2018, 03:35 PM
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#8
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Ve get too soon old, und too late schmart Group: Members Posts: 142 Joined: 11-October 12 From: Islip, Long Island, NY Member No.: 15,026 Region Association: North East States |
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 |
Jun 25 2018, 04:10 PM
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#9
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only the lead dog enjoys a change in scenery... Group: Members Posts: 452 Joined: 10-January 12 From: Santa Barbara, CA Member No.: 13,990 Region Association: Southern California |
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 |
Jun 25 2018, 04:31 PM
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#10
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Life's been good to me so far..... Group: Admin Posts: 15,820 Joined: 11-September 03 From: Hurst, TX. Member No.: 1,143 Region Association: NineFourteenerVille |
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 |
Jun 25 2018, 06:22 PM
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#11
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Advanced Member Group: Members Posts: 2,081 Joined: 7-February 08 From: Sacramento, CA Member No.: 8,684 Region Association: Northern California |
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 |
Jun 25 2018, 06:33 PM
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#12
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914 Freak! Group: Members Posts: 17,150 Joined: 4-January 03 From: Antioch, CA Member No.: 87 Region Association: None |
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 |
Jun 26 2018, 02:07 PM
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#13
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Senior Member Group: Members Posts: 1,205 Joined: 20-April 10 From: PA, USA Member No.: 11,639 Region Association: MidAtlantic Region |
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.
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rgalla9146 |
Jun 26 2018, 05:49 PM
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#14
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Advanced Member Group: Members Posts: 4,624 Joined: 23-November 05 From: Paramus NJ Member No.: 5,176 Region Association: None |
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 |
Jul 8 2018, 08:41 PM
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#15
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914 Freak! Group: Members Posts: 17,150 Joined: 4-January 03 From: Antioch, CA Member No.: 87 Region Association: None |
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 |
Jul 9 2018, 12:40 AM
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#16
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Advanced Member Group: Members Posts: 2,081 Joined: 7-February 08 From: Sacramento, CA Member No.: 8,684 Region Association: Northern California |
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 |
Jul 9 2018, 07:15 AM
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#17
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bdstone914 Group: Members Posts: 4,673 Joined: 8-November 03 From: Riverside CA Member No.: 1,319 |
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 |
Jul 9 2018, 08:41 AM
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#18
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Advanced Member Group: Members Posts: 2,081 Joined: 7-February 08 From: Sacramento, CA Member No.: 8,684 Region Association: Northern California |
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 |
Jul 9 2018, 09:20 AM
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#19
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914 Freak! Group: Members Posts: 17,150 Joined: 4-January 03 From: Antioch, CA Member No.: 87 Region Association: None |
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!
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