P38A Binding NSR brake

4.0 Thor.
Back story; was driving around with little meat on the NSR pads for a while until the nest finally gave out and it was metal on metal. Smell was horrendous but carried on, slowly with gentle braking to get me home (3 miles or so).

Decided to replace discs and pads on both rear sides. Still had binding on NSR. Have now replaced the calipers at both sides too but the problem remains on NSR. I'm not convinced it's just about a lack of running them in as the OSR doesn't smell or heat up while the NSR will heat the wheel to the point you can't touch it for too long.

Question is, are the pipes liable to collapse internally? Considering all the mechanical parts have been replaced (slide pins move freely, they're not sticking) I'm not sure what else it could be?

Glad I did it though as I've noticed the exhaust has split from the rear silencer on that side too!

Have the brakes been bled as per the procedure in RAVE? How old is the brake fluid?

Damaged flexi by crimping it, or sticky piston in the caliper ??

kevstar said:

Damaged flexi by crimping it, or sticky piston in the caliper ??

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Brand new calipers both sides, move freely when off the car.

Datatek said:

Have the brakes been bled as per the procedure in RAVE? How old is the brake fluid?

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Age of fluid possibly unknown but using a tester it shows as good. First time round (doing discs only) we ejected quite a bit so it was topped up with new. Did the same when fitting the new calipers.

As for following rave for brake bleeding, I would have to say no. Did a standard 2 man job with off/on nip up/let off.

However, it was the same procedure both sides so not sure why it would only effect 1 side?

domino said:

Age of fluid possibly unknown but using a tester it shows as good. First time round (doing discs only) we ejected quite a bit so it was topped up with new. Did the same when fitting the new calipers.

As for following rave for brake bleeding, I would have to say no. Did a standard 2 man job with off/on nip up/let off.

However, it was the same procedure both sides so not sure why it would only effect 1 side?

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You could try doing a proper bleed.

id think flexi hose if fluid isnt returning

Slider pins new?

jamesmartin said:

id think flexi hose if fluid isnt returning

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+1 you always get trouble with 2 men nipping up and letting off.

Does it bind 100% of the time, after using the pedal, or squeak as it goes round?

No squeek, binding always. I'm guessing that's why the last one wore out so badly but as I was doing shortish trips didn't really notice until it was metal on metal.

Grrrrrr said:

Slider pins new?

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Yup, new pins and appropriate lube.

1. Did the wheel spin easily after installing new pads ? I presume they were not touching disc until you pressed the brake pedal ?
2. Are they binding even with engine off, or only when running ? If only when running, maybe there's a faulty ABS sensor, and the traction control thinks the rear wheels are spinning at different speeds ?
3. What brand of discs & pads ? Are they correct thickness ?

Definitely worth bleeding using correct RAVE procedure. Maybe you have residual pressure in the rear ?

domino said:

No squeek, binding always. I'm guessing that's why the last one wore out so badly but as I was doing shortish trips didn't really notice until it was metal on metal.


Yup, new pins and appropriate lube.

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Then my vote would also go to internally collapsed flexi hose acting as a one way valve.

When I raised it again, the wheel was not spinning freely. Took the shims off and refitted the pads and it spun freely. Went for a 5 min drive round the block, came back, wheel was hot and you can smell it. It's parked up again now til I get a bit of time again.

Infrared temp guage showed 3 corners at 48ish degrees. The NSR at 330ish - 5 minute 'pootling' drive.

I'm seeing different part numbers for the flexi - can anyone give me an accurate one? To confirm, it's rear passenger side.

Thanks

You said you removed the shims, by that I take it you mean the ones where the pads locate on the carrier, (I don't know the P38), not all vehicle use them but they are the intricately bent and shaped stainless steel pad seats, usually just a top and bottom with the inner and outer portions connected together.

Did you de-rust the carrier beneath where the shims seat?

There can easily be a millimetre of rust on this part of the carriers, if you don't remove it then the pad will bind even with a new caliper.

Yeah, all cleaned up properly and with slip on the relevant parts.

The pads moved freely before the caliper was placed back in position.

Flexi next then.

Snap. I've had this for an eternity. Before and after a complete rebuild and replumb. Same corner. Ditto the carrier. I had to really go to town on de-crudding. A bit of bright metal showing is good.
I smeared , I mean smeared. copper grease on and it stopped the binding. The iron filings played billio with the wheel once the pads got down to the metal. The corner still wears slightly greater than the others, but, every service I give it the same treatment. (these days I tend to be servicing it every five minutes- I've started to reassemble everything with velcro and zips)

Was thinking that; take a grinder or dremmel to the carrier and really eat away **** and get down to fresh metal. Just don't wanna waste my time because I've got so little of it these days.