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Dual piston slider pins.

Posted: Sat Jun 08, 2019 9:19 pm
by north54
After a year and a half I feel like my front right brake caliper is failing. The slider pins are getting more and more corroded. I've already removed them, cleaned (sanded) them, regreased, installed about 3 times over 12 months. Whats odd is this is only happening on the front right, lefts are just fine.

I'm running dual piston on my L300.

Besides the corrosion I noticed both top and bottom pins on either side have the rubber grommet on the end. From what I've read there is supposed to be a pin with no rubber on top and a pin with the rubber grommet on the bottom. Can anyone confirm this? I'm running Beck Arnley Brake callipers. Thanks.

Dual piston slider pins.

Posted: Sun Jun 09, 2019 5:40 pm
by Growlerbearnz
MB618227 top pin (plain pin). CAD$11 from Amayama.com
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MB618228 lower pin (with rubber tip) CAD$10
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The lower pin is supplied without the rubber. To get the rubber you need rebuild kit MB857840 (superseded by 4605B977 CAD$30)
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To rebuild both sides you'd need 2 of each part number. The rebuild kit comes with all seals and the magic special grease that stops the pins from seizing for at least 30,000km. <--Sarcasm! but the genuine grease does seem to work better than regular grease.)

Normal petroleum based wheel bearing style grease doesn't seem to work very well or last very long. If you're determined to keep your old pins and rubber parts, I'd clean them out thoroughly, degrease them with a diesely rag and let them dry, clean out the tubes/holes on the calipers, and try reinstalling everything with silicone grease. Synthetic grease might also work.

Dual piston slider pins.

Posted: Sun Jun 09, 2019 9:38 pm
by north54
Thanks Growler. I'm not running genuine Mitsubishi calipers so not sure the OEM rebuild kit will work. Maybe I'll have to get some used OEM calipers and rebuild them.

Dual piston slider pins.

Posted: Tue Jun 11, 2019 3:45 pm
by Growlerbearnz
Wow, so the new Beck Arnley slider pins are corroding after only a year and a half? That sounds like crappy quality.

Interesting that it's only happening on one side. How did you find out that they were corroding? Random precautionary inspection, or did one side seize up? If it seized up, maybe check that both pistons are moving freely- open the bleeder and push both pistons into their bores, then close the bleeder and pump the brake pedal to push them back out (topping up the reservoir as needed). If one piston sticks it tilts the caliper and jams the sliding pins.

Are the pads wearing the same on both sides? If the right side is wearing unevenly (thinner on one end) you've got a sticky piston.

Could you swap the pins from left to right and see if the issue swaps sides?

Dual piston slider pins.

Posted: Tue Jun 11, 2019 10:16 pm
by north54
I think I started to look into it because it was hard to stop the van. More pressure needed on the pedal than I recall. I upgraded to dual piston to make it easier. I think I'll have to replace the right caliper as the slider pins are so pitted they are making reinstall hard. Maybe I didn't install one of the little rubber bellows correctly and water got in. Insides must be corroded as well. Pads look ok.

Dual piston slider pins.

Posted: Fri Jul 26, 2019 8:50 pm
by north54
Had time to revisit this today and took apart the right front caliper. Pistons are good, nice and shiny and seem to slide well. One of the piston boots was bulging out for some reason before I took them apart. I was afraid it would be pinched when it touched the brake pad. After refitting everything they seem to seat better. Pins are still corroded so I'll replace them asap.