Changing Breakpads on a Land Rover DII

[jeffryscott]

It's the thickness of the rotors on the DI so LR says to just replace. I found it odd when I had mine, although I knew people who did turn them, once. As I said though, DII may be different and it is probably moot since I think Brian has aftermarket rotors.

One of the many quirks which endear one to Land Rovers:ylsmoke:

 

[goodtimes]

Mangler, genuine question, but why do you turn your rotors with no warping present? I have always just cleaned & scrubbed the rotors and installed new pads and have never had degraded results from this?

I know a shop will always turn the rotors, but I've always felt that just because it could be partially justified, it was more money for 'em anyway.

If the friction surfaces are flat and parallel, and there is no physical damage to them, there is no need to turn them. Just follow the standard bed-in proceedure for the new pads to ensure you get the proper material transfer layer onto the rotor, and you are good. Even at track days, many people simply swap out the pads for the day (we all know not to use street compound pads at the track, and vice-verse, right?). Follow the bed in proceedure, and they are golden.

If you are getting grooves, the rotors are warped, or you managed to get an uneven transfer layer (like when you overheated your street pads at the track.....), then you gotta turn 'em.

 

[RAM5500 CAMPERTHING]

If you are getting grooves, the rotors are warped

No, i disagree with this!

First, Grooves are also caused by muck/dirt/debris being in between the pads and the rotors for any length of time!

This is exactly why my vehicles that see a lot of offroad use tend to be much more grooved then my street vehicles. :safari-rig:

Second, if rotors are "Warping" i think their integrity is compromised and will replace them instead of turning.

If something that thick and heavy is bending and warping, i think there are other factors that need to be address before "Cutting Them Flat"

Thats my .02

 

[goodtimes]

No, i disagree with this!

First, Grooves are also caused by muck/dirt/debris being in between the pads and the rotors for any length of time!

This is exactly why my vehicles that see a lot of offroad use tend to be much more grooved then my street vehicles. :safari-rig:

Second, if rotors are "Warping" i think their integrity is compromised and will replace them instead of turning.

If something that thick and heavy is bending and warping, i think there are other factors that need to be address before "Cutting Them Flat"

Thats my .02

To clarify, my statement should be read as "grooves, or are warped, or have damage"....not implying that grooves cause them to be warped...any of those 3 conditions warrant turning the rotors. It is actually very rare that rotors actually "warp". There is always some amount of runout from the manufacturing process, regardless of the finishing process being double disk grinding or straddle cutting....it is never perfect. I have seen literally millions of brake rotors, have done the QA checks on countless rotors, overhauled the equipment that machines them, and built the plants that produce them....and I have never seen a perfectly flat rotor. Some were damn close (8 microns), but never perfect. There will also be some amount of warping as they heat and cool, particularly with the less expensive (cast in asia) rotors.

Generally, people who feel a pulsation in the brake pedal assume that the rotors are warped, when in reality they have a uneven layer of transfer material. Either way, the effect on the vehicle is the same, so I just use the term "warped", as most people understand that I am referring to a problem that causes a pulsation in the brake pedal....turning the rotors will remove this, regardless of the actual problem being a transfer layer issue or a warped rotor. But if the friction surface has been damaged on a molecular level (overheating, corrosion, etc), it will cause the uneven layer to keep showing up despite turning the rotors, in which case they should be replaced, because turning will not remove this.

Driving off road has little effect on the grooves in the rotor. My jeep has 70K on it, literally hundreds of off road trips, original brake pads/rotors, and very little grooving. If you spend alot of time in mud, yes, that has a much more drastic effect on your pads and rotors. But regardless of driving conitions, if the friction surfaces are not flat and parallel, they should be turned (or replaced).

 

[RAM5500 CAMPERTHING]

To clarify, my statement should be read as "grooves, or are warped, or have damage"....not implying that grooves cause them to be warped...

Gotcha! Good point! I shoulda caught that!

any of those 3 conditions warrant turning the rotors.

Yes, i agree! I also agree that if you own a vehicle designed by a manufacturer to force you to BUY new rotors and not have enough meat on them to turn, its time to shop for a new rig!

If that comment about the DII is true that is just ridiculous!!! :sombrero:

It is actually very rare that rotors actually "warp".

Correct, You will almost NEVER see OEM rotors warping, enough to cause concern anyway. Usually the cheap $50 aftermarket ones are the ones that have problems!

and I have never seen a perfectly flat rotor. Some were damn close (8 microns), but never perfect.

Yup, i have a gearhead friend that even turns rotors that he buys new to assure they are 100% true. Not sure i agree with this process, or that the machines he are using are that accurate, but thats his routine

There will also be some amount of warping as they heat and cool, particularly with the less expensive (cast in asia) rotors.

Yes, see above comment!

Driving off road has little effect on the grooves in the rotor. My jeep has 70K on it, literally hundreds of off road trips, original brake pads/rotors, and very little grooving. If you spend alot of time in mud, yes, that has a much more drastic effect on your pads and rotors. But regardless of driving conitions, if the friction surfaces are not flat and parallel, they should be turned (or replaced).

Well Said!

I am from the East Coast where offroading almost ALWAYS had some Mud involved.

Now that you mention it, my rotors on my west coast rigs are much cleaner and straighter! :safari-rig:

 

[goodtimes]

Yup, i have a gearhead friend that even turns rotors that he buys new to assure they are 100% true. Not sure i agree with this process, or that the machines he are using are that accurate, but thats his routine

I'll give you 10 to 1 odds that the machines he is using are no where near as accurate as the machines that are being used in the factory. Even when we were doing strictly aftermarket rotors, we were double disk grinding on a Landis Gardner 600mm double disk grinder. $3/4 million each, work holding spindle had an allowable runout of .00007" on the face....when I rebuilt the last one I couldn't even measure it (all I had was a .0001" test indicator).

With a quality casting, clean tooling and sharp inserts, we could hold 8 microns runout....which was 1 micron to many to land us the Crown Vic contract. Bastards.

 

[RAM5500 CAMPERTHING]

I'll give you 10 to 1 odds that the machines he is using are no where near as accurate as the machines that are being used in the factory.

Without a doubt, i agree 100%

 

[david despain]

toss em' in the trash.

the rotors are basically throw away on a DII. the min thickness is stamped on the rotor( i think all dot aproved rotors are stamped) but i bet they are close enough now that they wont make it to the next brake change. the ETC tends to chew up rotors fairly quickly.
If you do just the pads they are cake. nothin special to them at all. If you do the rotors also they are not difficult either, but do require a little disassembly. they are nothing like the DI, RRC, D90 however. only thing that might hang you up is the locator screw on disc. it is a posi-drive size #4. it is NOT the same as a phillips screw head. http://www.matcotools.com/Catalog/toolcatalog.jsp?cattype=T&cat=2117&page=1&#34075 bz4b is the part number. or use this one http://buy1.snapon.com/catalog/tools.asp?tool=all&Group_ID=279&store=snapon-store or you could drill it out. or you could get lucky and use a phillips. i prefer to use the right tool for the job. i just reuse the screws but they are less than a buck a piece i think from atlantic british or british pacific or your vendor of choice.

you may have to beat the rotor off the hub with a BFH. i cleaned up the hub with scotch brite pad and applied a thin coat of antisieze to the hub on reinstallation. i also cleaned and relubed the caliper slide pins with some fresh grease. take note that the slides have a flat spot on them that fits against the bracket to keep them from turning so you can tighten the caliper bolts.

if i recall you need a 9/16 for the caliper bolts, it pops off and pads come right out. all you need is a big c-clamp and the old pad to squeeze the pistons back in. make sure to suck some fluid out of the master cylinder first. are you just doing the fronts? when i did just the fronts a few weeks ago i found that by sucking all the fluid out, then squeezing the pistons back then sucking all the fluid out again, it would take a small container ( i think 12 oz.) of brake fluid to bring it just a hair shy of the full mark. remember, the rave cd says castorol LMA fluid is the juice of choice.

If you do the rotors i think its an 18mm socket( although i used 3/4") for the caliper mount bracket, BUT it is a 12 pt. bolt. if you dont do the rotors it really is a quick easy job.

This is a good use of the Jeep phrase:

"Its a Rover Thing, and I Dont Understand!!!

Thats just plain silly if true!

LOL i may have to make this my new sig!

i put EBC green stuff pads on generic rotors a few weeks ago and i really like the pads. the oem pads make a lot of dust that is impossible to get off and these dont make any dust that i can tell.

 

[goodtimes]

t the min thickness is stamped on the rotor( i think all dot aproved rotors are stamped)

You are correct. The minimum thickness is marked on every rotor...sometimes it is cast in, sometimes it is stamped in, sometimes it is etched in with a laser...but it is always there when the rotor is produced. Stamping and etching are usually done on the outer edge of the friction surface, so a little rust makes them pretty much illegible.