My S70 is Eating Calipers

WhatAmIDoing · Post by **WhatAmIDoing** » 25 Aug 2018, 20:30

Just installed the 3rd RF caliper this YEAR on my precious S70 T5M. Yes I've been through 3 calipers in the past year (and I think soon to be 4) and that's just on the passenger front, and I've already installed the 2nd on the driver's side. Last summer, the original calipers started sticking, the passenger side seizing completely. I flushed out all the old brake fluid and installed Cardone rebuilts on the front. Fast forward to this summer, and the LF caliper seized abruptly. Figured garbage Cardone quality and installed another on FCP's dime, as well as replacing the flex line. A few weeks later, the RF seized abruptly. Had to pay an indie to get the caliper off the rotor and replace the flex line (the flare nut was not budging). The indie flushed and inspected the hard lines, installed a new Cardone caliper (thanks FCP), and installed a new flex line. They also turned both front rotors, and amazingly they weren't warped. I put a few hundred miles on that caliper before it abruptly seized. Replaced with a Duralast rebuilt caliper a few days ago (that was all I could get short notice), took a road trip, and, to my amazement, the RF rotor is scalding hot while the other three are barely warm to the touch.

So the Duralast rebuilt either failed in less than 300 miles of mostly highway driving, or something else is going on here? I honestly don't know what to do, other than buy and install yet another caliper (#4 in the past 365 days).

In summary, the rotors are not warped, all parts installed were new/refurbished ATE, calipers and slides were lubed properly with ATE brake grease, new flex lines, the front hard lines have been flushed, and new brake fluid. Is there something I'm missing, or am I just having a serious string of bad luck? I do not ride my brakes or abuse them. I just don't get it.

Post by **RickHaleParker** » 26 Aug 2018, 02:10

Does the RF Caliper slide freely on the guide pins? It does not matter what you did, its what the Caliper does.

Post by **abscate** » 26 Aug 2018, 04:08

I’m thinking a blocked port on the master cylinder might be maintaining pressure on one caliper...

But I really don’t like that answer.

New rotor,,maybe the rotor is warped badly to where the brake can’t release ? Worth removing and check8ng again.

That’s a tough one.

Post by **ZionXIX** » 26 Aug 2018, 05:46

As annoying as it sounds, you could try replacing the hard line from the master cylinder to the abs and from the abs to the flex line. Could also try replacing the master cylinder with a parts store brand just for testing. It's really odd that this is happening on 1 side only.

WhatAmIDoing · Post by **WhatAmIDoing** » 26 Aug 2018, 09:11

Caliper slid freely when I installed it. Worked beautifully for 300 miles. The hard lines were flushed after the ABS by my trusted Indie (he's baffled too). The master cylinder theory does not make a lot of sense to me, especially if it is just one caliper and there are no other issues. Rotors were turned before reinstalling. I was amazed they weren't warped.

I really don't want to replace the master cylinder or the hard lines, but it's looking like that might be the option. I have a pair of Centric rebuilt calipers coming on FCP's dime. Will see if it was just bad luck.

Post by **scot850** » 26 Aug 2018, 13:18

The quality of some re-built calipers is down the the quality of the parts they replace. Some re-use the pistons (I kid you not) and some use plain steel rather than chrome steel pistons which start to rust immediately. I noticed a huge difference in 2 re-built brands I have used. One called Nu-geon (?) I have used seem to be of a better quality than others I have seen.

Neil.

Post by **RickHaleParker** » 26 Aug 2018, 14:05

If the outlet valve for the RH front wheel where sticky the RH front wheel caliper would not release as it should.

"The control module controls, via the inlet and outlet valves and the hydraulic pump, the pressure to the different brake calipers when braking under ABS, EBD or TRACS.
The valve block has three internal circuits, one for the LH front wheel, one for the RH front wheel and a common circuit for the rear wheels.
The front wheels are controlled individually, while the rear wheels are under common control, depending on which wheel threatens to lock first.
The valve block has six valves for controlling the brake pressure, three inlet valves and three outlet valves. So, each front wheel has an inlet valve and an outlet valve, while the rear wheels have a common inlet valve and outlet valve between them. In stand-by mode, the inlet valves are open and the outlet valves closed. The outlet valves act as non-return valves between the brake calipers and the hydraulic pump."

Post by **erikv11** » 26 Aug 2018, 14:23

So to recap, within a year:

3 bad RF calipers
1 bad LF caliper

Both suggestions so far seem viable - master cylinder or crap caliper rebuild quality. I'd probably install the Centric calipers and watch. If the RF goes bad soon then abscate's idea about a clogged port for right front on the MC is looking most likely. If the LF goes bad soon then throw your hands in the air. If neither of them goes bad for a year or so it was probably bad luck i.e. just the ultra-low quality rebuild efforts.

That's got to be so frustrating, I feel your pain ...

Post by **BEJinFbk** » 26 Aug 2018, 15:03

I see three suggestions - Mr Parker's suspicion of the ABS module is very viable.
You've been through everything else and there are moving parts in there that may seize.
You might consider contacting Matty Moo at Midwest ABS and running this concept past him.

WhatAmIDoing · Post by **WhatAmIDoing** » 26 Aug 2018, 15:04

RickHaleParker wrote: ↑26 Aug 2018, 14:05 If the outlet valve for the RH front wheel where sticky the RH front wheel caliper would not release as it should.

"The control module controls, via the inlet and outlet valves and the hydraulic pump, the pressure to the different brake calipers when braking under ABS, EBD or TRACS.
The valve block has three internal circuits, one for the LH front wheel, one for the RH front wheel and a common circuit for the rear wheels.
The front wheels are controlled individually, while the rear wheels are under common control, depending on which wheel threatens to lock first.
The valve block has six valves for controlling the brake pressure, three inlet valves and three outlet valves. So, each front wheel has an inlet valve and an outlet valve, while the rear wheels have a common inlet valve and outlet valve between them. In stand-by mode, the inlet valves are open and the outlet valves closed. The outlet valves act as non-return valves between the brake calipers and the hydraulic pump."

Is there a way to bypass the control module or disable it for the sake of testing? Would I get an ABS light? Also, if the brake fluid could not return causing the caliper to fail to release, then if I open the bleeder valve, in theory brake fluid should squirt out and the caliper should release?

All the calipers i pulled off were seized. I could not force the piston back in with channel locks, a c-clamp, or a big vice with the brake hose disconnected and the bleeder full open. So did they fail because they seized due to crap quality, or did they seize due to excess heat from being unable to release?