300tdi brakes nightmare

defender/discovery · Jan 18, 2015

Hi all

having a lot of problems with the brakes on my disco first of all its a 1998 with abs I bought it with a few problems the biggest was brakes with what I put down to warped discs so I went all out and bought new calipers all round and new discs and pads all round all done with all the wheel bearings at the same time all fitted with no problems brakes seemed great once bedded in but then around 600 miles later the brake judder was back so I put this down to being cheap discs maybe I replaced the front discs with Delphi ones and once again all was fantastic until around 450 miles later the judder made a appearance again im at my wits end with it spending my only day off a sunday trying to solve it I took all precautions when fitting the second set of discs cleaned all the hubs up with a wire wheel on the drill till all clean followed all the fitting guidelines using correct torques on everything but cant get my head round the problem the discs don't look cooked neither do the pads and there has never been hot burning brakes smell to indicate over heating im just lost with the problem on the old girl now

any help or advise will be greatly appreciated

ronsealdeath · Jan 19, 2015

Is the abs kicking in? You can unplug it for a test not on public highway. Take it to an empty carpark unplug multi connection to abs block and see if it helps. If so, try bedding in sensors etc
.

RJ092 · Jan 19, 2015

could it be endfloat since you said you done bearings recently?

defender/discovery · Jan 19, 2015

Have disconected the abs numerous times but to no avail and as for end float I did not measure end float but done the bearings to all the correct torques and haven't had trouble doing that in the past just this discovery

markomate · Jan 19, 2015

Hi
Im ready to get flamed on this but, brake judder is rarely caused by "warped" discs.

Good 10 min read here
-Warped- Brake Disc and Other Myths

Ive driven many cars for many years and done support for track cars and I dont think ive ever seen a genuinely warped disc.

Judder is usually caused by pad material building up on the friction surface, as the brakes are applied, usually gently as normal road driving dictates, the steering wheel starts to judder, the juddering is caused by the pads "seeing" an uneven friction surface on the discs.

The cause of material build up is often sticking calipers, not pistons which rarely stick (unless a previous owner has used DOT 5 brake fluid!) but the sliding pins, this often happens when a garage takes the lazy way out when changing pads and only removes one bolt/pin and pivots the caliper up, the other pin doesnt get cleaned/lubed so it eventually starts to seize.

The caliper then doesnt push the pads evenly on to the disc, one part of the pad just "rubs" the disc slowly depositing a layer of pad material, after a while the pads start to "grab" the material build up causing judder

The cure for judder is removing the discs and cleaning off the build up, if its not too bad you can do it with an abrasive disc (not a grinding disc!) on an angle grinder, if its bad you can have the disc skimmed, this used to be the garage favourite for "warped" discs, and sure it cured the symptom but not because the discs were warped.

However these days discs are basically disposable so its just as cheap to replace them, as you have done.

So on the basis that you have re-booted your brakes by replacing everything, and that the problem keeps coming back, it could be that your brakes are demonstrating the symptom but are not the cause.

Your not using DOT 5 are you?! Are your wheel bearings ok?

You could try finding a quiet road, checking nothing is behind you, and doing a few hard stops from about 50 mph to zero in about 5-6 seconds, thats what I had to do to my D2 after I bought it, changed the pads, freed up the seized caliper pins, checked everything else. It certainly cured the juddering steering!

If your bearings are ok, it could be that Discos are prone to crudding up discs even if everything is ok, im very light on my brakes, are you? Maybe a few hard applications every few hundred miles will stop it happening?

Im new to Discos so im up for some feedback from more experienced owners!

BTW, when you slow your car down from 50MPH to 0 in 5 seconds, your brakes are converting 114 kW's of kinetic energy, mainly into heat, so discs have to be/are designed to handle that!

Sorry for long reply, I,ll blame it on my cold and the Vodka "Cure"

trax · Jan 19, 2015

markomate said:
Hi
Im ready to get flamed on this but, brake judder is rarely caused by "warped" discs.

Good 10 min read here
-Warped- Brake Disc and Other Myths

Ive driven many cars for many years and done support for track cars and I dont think ive ever seen a genuinely warped disc.

Judder is usually caused by pad material building up on the friction surface, as the brakes are applied, usually gently as normal road driving dictates, the steering wheel starts to judder, the juddering is caused by the pads "seeing" an uneven friction surface on the discs.

The cause of material build up is often sticking calipers, not pistons which rarely stick (unless a previous owner has used DOT 5 brake fluid!) but the sliding pins, this often happens when a garage takes the lazy way out when changing pads and only removes one bolt/pin and pivots the caliper up, the other pin doesnt get cleaned/lubed so it eventually starts to seize.

The caliper then doesnt push the pads evenly on to the disc, one part of the pad just "rubs" the disc slowly depositing a layer of pad material, after a while the pads start to "grab" the material build up causing judder

The cure for judder is removing the discs and cleaning off the build up, if its not too bad you can do it with an abrasive disc (not a grinding disc!) on an angle grinder, if its bad you can have the disc skimmed, this used to be the garage favourite for "warped" discs, and sure it cured the symptom but not because the discs were warped.

However these days discs are basically disposable so its just as cheap to replace them, as you have done.

So on the basis that you have re-booted your brakes by replacing everything, and that the problem keeps coming back, it could be that your brakes are demonstrating the symptom but are not the cause.

Your not using DOT 5 are you?! Are your wheel bearings ok?

You could try finding a quiet road, checking nothing is behind you, and doing a few hard stops from about 50 mph to zero in about 5-6 seconds, thats what I had to do to my D2 after I bought it, changed the pads, freed up the seized caliper pins, checked everything else. It certainly cured the juddering steering!

If your bearings are ok, it could be that Discos are prone to crudding up discs even if everything is ok, im very light on my brakes, are you? Maybe a few hard applications every few hundred miles will stop it happening?

Im new to Discos so im up for some feedback from more experienced owners!

BTW, when you slow your car down from 50MPH to 0 in 5 seconds, your brakes are converting 114 kW's of kinetic energy, mainly into heat, so discs have to be/are designed to handle that!

Sorry for long reply, I,ll blame it on my cold and the Vodka "Cure"

hi, i'm here to :flame2:

disco 1's have pots not sliders.

dot5 is silicone based, so highly doubt he's running that/ i also don't understand why it would lead to sticking pistons.. as it's hydrophobic.

seized pistons are very common

oh and i think discs do warp

markomate · Jan 19, 2015

Didnt know D1,s dont have sliding calipers, I do now!

Two cars I once owned, an MG Midget and a 993 Porsche both had DOT 5 put into them by previous owners, both had seized/partially seized pistons all round! If its put in without cleaning every bit of the normal fluid out first, it forms a mucky gel, this is what I found after Id managed to extract the pistons which were almost solid on the MG and very stiff on the 993.

But could just have been my bad luck!

The brakes on both cars never gave any more issues after the correct, DOT4, fluid was put back in.

Correction: Just remembered it was the MG that had DOT 5, the 993's brakes had seized due to water in the fluid, due to poor bleeding and sitting in a garage for over a year, all the calipers needed stripping down though. Ok off to bed now!

trax · Jan 20, 2015

markomate said:
Didnt know D1,s dont have sliding calipers, I do now!

Two cars I once owned, an MG Midget and a 993 Porsche both had DOT 5 put into them by previous owners, both had seized/partially seized pistons all round! If its put in without cleaning every bit of the normal fluid out first, it forms a mucky gel, this is what I found after Id managed to extract the pistons which were almost solid on the MG and very stiff on the 993.

But could just have been my bad luck!

The brakes on both cars never gave any more issues after the correct, DOT4, fluid was put back in.

Correction: Just remembered it was the MG that had DOT 5, the 993's brakes had seized due to water in the fluid, due to poor bleeding and sitting in a garage for over a year, all the calipers needed stripping down though. Ok off to bed now!

yeah the glycol doesn't mix well with the silicone. so the gel made them seize up? new one on me

i thought you meant with rust.

i think you'll find the defender pistons seize a fair bit. normal cars seem to have a rubber boot to protect the exposed piston, defenders/discos don't so they can rust up if not used much

trax · Jan 20, 2015

defender/discovery said:
Hi all

having a lot of problems with the brakes on my disco first of all its a 1998 with abs I bought it with a few problems the biggest was brakes with what I put down to warped discs so I went all out and bought new calipers all round and new discs and pads all round all done with all the wheel bearings at the same time all fitted with no problems brakes seemed great once bedded in but then around 600 miles later the brake judder was back so I put this down to being cheap discs maybe I replaced the front discs with Delphi ones and once again all was fantastic until around 450 miles later the judder made a appearance again im at my wits end with it spending my only day off a sunday trying to solve it I took all precautions when fitting the second set of discs cleaned all the hubs up with a wire wheel on the drill till all clean followed all the fitting guidelines using correct torques on everything but cant get my head round the problem the discs don't look cooked neither do the pads and there has never been hot burning brakes smell to indicate over heating im just lost with the problem on the old girl now

any help or advise will be greatly appreciated

did you change the pads with the second set?

if not you probably killed the discs.

markomate · Jan 20, 2015

Quick thought, 993,s suffered badly from whats called "caliper plate lift". The caliper was Alloy, but it had steel liners so the pads edges could slide in the caliper without digging into the "softer" alloy.

Corrosion (due to dissimilar metals) would build up between liner and the caliper, pushing the liner out, causing the pad to stick, this would do two things, cause the pad rubbing I described before, and eventually, the pistons to seize, juddering brakes were the symptom, the pistons stuck because they couldnt move against the stuck pads.

It was small, fairly easy thing to fix but it caused many sets of discs, pads and even entire calipers to be changed unnecessarily.

I assume D1 calipers are not alloy? Worth checking that your pads are not sticking in the caliper body though.

defender/discovery · Jan 20, 2015

Hi all thanks for the input glad to finally get other opinions I'm running dot 4 and have changed it to fresh dot 4 the calipers are only 6 months old and are bearmach products so can't see it's them that have gone so quickly I think I will try clean my calipers and discs up and see if there any change also yes the pads have been changed both times using ebc ultimax this time round

trax · Jan 20, 2015

what makes did you use exactly for the discs and pads btw? and did you bed them in or just go off driving as normal?

defender/discovery · Jan 20, 2015

Ebc ultimax pads and Delphi discs both quality makes and I bed them in for around 200 miles of really gentle braking and then after that still take it easy before completely using them heavily I don't even use my trailer for the first 200 to make sure they are bedded in

trax · Jan 20, 2015

ok, many differ and love them, but i hate ebc stuff.. i think it's junk.

i'd be tempted to get some pagid pads and see what happens.

i used ebc ultimax or whatever it was (expensive ones) and some greens a few years back on a vag and it warped the discs after a k or 2, i wasn't too happy. stuck ferodo and pagid discs and no issues again.

pagid, ferodo, mintex and a few more are quality makes.

300tdi brakes nightmare

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