Henrik97

Active Member
Car is a 2007 tdv8 with the brembo fronts. How likely is it for all four calipers to go sticky at the same time? I had the front pads off today and had to wrestle them out. However, once I had them out, the pistons moved easily. I just find it slightly incredible that all four should go at the same time. All discs get hot and you can feel the car isn't rolling as freely as it should. I guess my question is if there is some other malfunction that can cause the brakes to pressurise slightly?
Getting frustrated here...

Henrik
 
A working caliper piston is only part of story to having functional brakes.

Of equal importance is that the pads are slightly loose on the seat of the carrier, something like 0.5 - 0.75mm, which allows to the pad to expand with heat without binding. Copper grease on the locating tips is a must.
Carrier must be scraped clean of rust to bare metal also.
If they have stainless metal formed shims the rust forms unseen below them.

The sliding mechanism pins are next, these need cleaned and greased with silicone grease, they should be nice and free but not sloppy axially.

Next, fluid must be in good condition as it's hygroscopic and if this simple maintenance item is ignored you will get gunk and rust in the lines which contribute enormously to stickiness of the piston.

Lastly, and often overlooked are the flexi lines, for the cost of them, and on these heavy machines and at the age yours is at, get em changed, you'd be amazed how badly they suffer internally from dizzy mechs clamping them with the wrong tools.

You have Brembo fronts, but standard rears if I recall correctly.

EDIT!! Your front Brembo calipers are of fixed body design, they have no sliding pins. (other than the pad retaining ones at the front)
 
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Thank you. This is all good advice, and it may well be that bad fluid or worn parts has caused the issue, I just find it very odd and unlikely that all four wheels, with , as you point out, very different designs of caliper front to rear, should go sticky at the same time. I have ordered new calipers for the rear and overhaul kit for the fronts. I hope it will do the trick, but after inspecting the front calipers yesterday, I have my doubts. They seemed in good order to me.
 
Well, last night a m8 of mine called saying one his rears was red hot, could I look at it.....(Non LR vehicle)

Straight to it, pumped the piston out, clamped the flexi and caliper whipped of to the bench.
Piston cleaned up perfectly, caliper cleaned perfectly, seal removed and groove cleaned etc etc.

Back together it was free as a bird, bled entire brake system as it turned out to nearly five years since it changed.

If I had piston seals I would of changed them, given the roasting.
 
After a wee google......
Back to your concerns re. 'why all four brakes sticky'.....
It seems it's not out of the question for electrickery to affect the brakes on 322s.

http://www.fullfatrr.com/forum/post46165.html

The second last post has a link, click on that, there are other links also.

If it were me I'd get some Diag.
TestBook is dealer (or subscribed Indy) but others work just as good, but I don't know them off hand.
 
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I've had a look at that thread, but it seems these faults involve warning lights and abs-activity. I have none of these. It acts as if I have my foot gently resting on the brake pedal at all times. It seems slightly intermittent and it gets better after a good drive without applying the brakes, so as unlikely as it seems, I'm leaning towards sticky calipers all round.
 
I've had a look at that thread, but it seems these faults involve warning lights and abs-activity. I have none of these. It acts as if I have my foot gently resting on the brake pedal at all times. It seems slightly intermittent and it gets better after a good drive without applying the brakes, so as unlikely as it seems, I'm leaning towards sticky calipers all round.
I doubt all 4 calipers would be sticking and I think you said that the pistons were free?
I would be getting some diag on it first to see if anything is ammiss.
Any car which can control the brakes electronically is susceptible to applying the brakes when it shouldn't due to incorrect feedback from the sensors
 
It was just a thought....
I'm of the belief that, just like the pre 05 models, that the handbrake mechanism is the usual shoes within the rear discs, and still operated by cables, but actuated by a rather expensive mechanism mounted above the subframe.
No doubting it will have an ECM, as from googling it seems there is a mode for 'bedding' in new linings.

This probably has no bearing on the OPs issue, I only mentioned it to see his response, as in his original post he mentioned difficulty in extracting the brake pads.

I should of probed further with that as there are 2 likely scenarios around that...

1. He didn't apply sideways pressure on the pad to push the pistons back slightly,
2. Or he did that but the pads were binding to the carrier.

He went further to say his pistons were free so I'm hoping the tip I mentioned about the pads needing to be fractionally loose where they locate on the carrier has got him scraping away feverishly, and if they are still tight not to be afraid to get the bastard file out to relieve the pads of a little wisp of material (or paint!!) Not all pads are created equal.

I'd also be having the rear discs off for a look see, or at the very least checking that the rears are free with handbrake OFF.
 
Hi all,
I do have the electronic handbrake, but it's the discs getting hot, not the drums. The fronts have definitely got better after my little service the other day, when I had the pads out, copaslipped them and reinstalled them in reverse order to (hopefully) get the pistons to a slightly adjusted working position. They are still binding slightly, but it's intermittent and nowhere near as bad as it was. On the rear, it seems the problem is now isolated to one side only. So, it's all looking a bit different now to what it was a few days ago. New rear calipers are in the post, as are pistons and seals for the front and new shoes. It's looking more and more likely that they will do the trick.

Thanks everyone!
 
When I did the brakes on the p38 I looked a calipers on fleebay and thought the same, not worth the hassle fit new they were cheep enough, new disks pads and calipers all round job done.
 
I ask because if they aren't fitted with the cuts or slots facing the rear of the car when you look at the top of the disk they can cause noises and interference in the caliper..
IMG_20171117_175119.jpg

In the photo, the rear of the car is to the left...
Hope this makes sense??
 
Inertial ejection, like a Catherine wheel.

I never considered they should be sided.
Unfortunately I'd fitted some on the car pictured wrong sided. A constant chattering and shuddering under braking on the test run... Hadn't realised I'd fitted the buggers on the wrong side:mad:... After the refit all the symptoms where cured.. just wandered if in the op's case if it was applicable?o_O.. crappy old brake fluid never changed can cause it's own issue's as well..most cars every two years due to hydroscopic behaviour!!
:confused:
 
Just a wee update for those interested:
Rear calipers replaced, fronts overhauled with new pistons and seals, fluid changed.
All back to normal! :)
So, it seems that the morale is: If you service your car yourself, do not forget or ignore brake fluid change!

Cheers,
Henrik
 

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