Replacing front brake disks on Range Rover P38A

Hi chaps,

Bit more advice if you're willing. Having bought the 1994 Rangie I'm slowly working through giving her some TLC. I've bought new discs and pads for the front and just had a look at fitting them. There appear to be 2 barriers:

First, the bolts that hold the brake calipers on look like some sort of star headed bolt. A 21mm hex-socket fits on but I daren't try doing anything in case the layers of rust shears off leaving me with a nasty problem.

Second, the screw that holds the disc on isn't a standard philips. It is very shallow, much bigger than any of my screwdrivers and has like a smaller philips head within the bigger one at 45 degrees. Also looks like someone's polished it slightly in the past shearing some corners. Is this some sort of special tool requirement or is it just a stuffed screw?

Many thanks,

J

Hi

The bolts are 19mm 12-point, so a 12-point socket should fit, you may need to tap it on gently if the bolts are a bit rusty. If you haven't got a decent quality 12-point 19mm socket, then go and buy one! Don't even think about using a 21mm!! They will be tight so you need to put quite a bit of force on them, also when doing them up.

The screw can just be drilled out and ignored when you put the new disks on. I tried grinding down an old phillips bit from an impact driver, but even that wouldn't shift it. I found that just drilling the head off left enough of the screw in situ that it came undone easily once the disk was off.

Hope this helps!

Cheers

Jerry

Ah, an excuse to buy more tools. Excellent!

Screw looks to be a PZ4 posidrive. Realise it isn't strictly required but I like things right so I think I'll buy a bit and try to get it out. The replacement is only 40p so I might as well have one in reserve in case I have to drill it.

Thanks Jerry. Time for some online plastic therapy!

J

Grrrrrr said:

Hi chaps,

Bit more advice if you're willing. Having bought the 1994 Rangie I'm slowly working through giving her some TLC. I've bought new discs and pads for the front and just had a look at fitting them. There appear to be 2 barriers:

First, the bolts that hold the brake calipers on look like some sort of star headed bolt. A 21mm hex-socket fits on but I daren't try doing anything in case the layers of rust shears off leaving me with a nasty problem.

Second, the screw that holds the disc on isn't a standard philips. It is very shallow, much bigger than any of my screwdrivers and has like a smaller philips head within the bigger one at 45 degrees. Also looks like someone's polished it slightly in the past shearing some corners. Is this some sort of special tool requirement or is it just a stuffed screw?



Many thanks,

J

Click to expand...

You probably know this already ,but just in case,remember to de-pressurise the braking system before stripping the brakes by pressing the pedal at least 30 times with the key off. Sorry if i am telling you how to suck eggs

rodntod said:

You probably know this already ,but just in case,remember to de-pressurise the braking system before stripping the brakes by pressing the pedal at least 30 times with the key off. Sorry if i am telling you how to suck eggs

Click to expand...

If all you are doing is changing the pads and disks, I don't think depressurising the system is necessary - at least, I didn't do so on mine, and had no trouble pushing the pistons back into the calipers either.

Cheers

Jerry

jerrytlr said:

If all you are doing is changing the pads and disks, I don't think depressurising the system is necessary - at least, I didn't do so on mine, and had no trouble pushing the pistons back into the calipers either.

Cheers

Jerry

Click to expand...

no its not if working at wheels

oops sorry, my bad

When already there, check the state of caliper sliding bolts, all should be moving around easily. They are between caliper bracket and caliper, under black rubber boots.

Also, i've chamfered the leading and trailing edges on the brake pads, it stops them squealing, but that's totally dependent on disc/pad configuration you have...

An impact driver will probably remove the screw. It's a fairly safe bet that an ordinary screwdriver won't touch it.

I would plan on replacing the screws in any case. The impact driver tore mine to pieces, but it still managed to remove them ok.

I can't believe no one has suggest a hammer and a sharp punch to knock the screw round until it is out

My suggestion is either a BIG hammer, smack the screw a few times. Other than that, soak the screw in penetrating oil, possibly the "freezing" kind combine both, and a gentle touch with a blowtorch, and voila.

I'd go with impact driver! It's what they do

matt1987 said:

I can't believe no one has suggest a hammer and a sharp punch to knock the screw round until it is out

Click to expand...

:clap2::clap2:
This method has always worked for me without any problems. Those Pozidrive headed screws are a pain in the ass.
Buy a few countersunk socket head screws from Ebay or fastener supplier for very little money and secure them with an allen key. No need to tighten them up to 1000ft. lbs. either as the wheel holds the disc against the hub.

Irishrover said:

:clap2::clap2:
This method has always worked for me without any problems. Those Pozidrive headed screws are a pain in the ass.
Buy a few countersunk socket head screws from Ebay or fastener supplier for very little money and secure them with an allen key. No need to tighten them up to 1000ft. lbs. either as the wheel holds the disc against the hub.

Click to expand...

How is Irish these days? All settled back in the UK?? Hankering after another P38 to alleviate boredom yet???

Datatek said:

How is Irish these days? All settled back in the UK?? Hankering after another P38 to alleviate boredom yet???

Click to expand...

:behindsofa:

Bon jour Keith....tootling round North Wales trying to find good Ale Houses (Few & far between this neck of the woods !!), so like yourself have to settle for a few bottles of Vino Collapso or beer out of a bottle. Getting sorted out gradually though.
I'm surprised at the number of 4X4's up here though from Porche Cayennes to new (2011 & 2012) Rangies...ain't the loweer end models either !! Quite a few of them feckin Evoques as well-LR or TATA ought to be hung drawn & qurtered for developing such a heap of ****e.
Yes, I do miss the Rangie but not the fill up costs !!-still, I say "If you can't stand the heat, get out of the kitchen !!".
The Vectra has WORKING climate control and is averaging 32 mpg which ain't bad considering some of the hills round here !!
Have done a bit for an independant in Birmingham with his diagnostics (Test Book and Faultmate) on P38's, Disco's and new Rangies for a couple of days but it's a 320 mile round trip-buys a few bottles though !! Tell you what, Test Book is crap compared with the Faultmate...too much pi**ing around with a roll around cart and more cables than they have at the Olympics. Can't complain though, he buys the lads in the workshop Fish & Chips for lunch every day.
Er indoors is keeping me that busy I don't have time to even think about another P38 but might be tempted if a nice Westminster or Holland & Holland comes along...Petrol-not LPG of course !!

Irishrover said:

:behindsofa:

Bon jour Keith....tootling round North Wales trying to find good Ale Houses (Few & far between this neck of the woods !!), so like yourself have to settle for a few bottles of Vino Collapso or beer out of a bottle. Getting sorted out gradually though.
I'm surprised at the number of 4X4's up here though from Porche Cayennes to new (2011 & 2012) Rangies...ain't the loweer end models either !! Quite a few of them feckin Evoques as well-LR or TATA ought to be hung drawn & qurtered for developing such a heap of ****e.
Yes, I do miss the Rangie but not the fill up costs !!-still, I say "If you can't stand the heat, get out of the kitchen !!".
The Vectra has WORKING climate control and is averaging 32 mpg which ain't bad considering some of the hills round here !!
Have done a bit for an independant in Birmingham with his diagnostics (Test Book and Faultmate) on P38's, Disco's and new Rangies for a couple of days but it's a 320 mile round trip-buys a few bottles though !! Tell you what, Test Book is crap compared with the Faultmate...too much pi**ing around with a roll around cart and more cables than they have at the Olympics. Can't complain though, he buys the lads in the workshop Fish & Chips for lunch every day.
Er indoors is keeping me that busy I don't have time to even think about another P38 but might be tempted if a nice Westminster or Holland & Holland comes along...Petrol-not LPG of course !!

Click to expand...

Glad to hear all is well, forget the petrol and get a diesel, muuuch beter

Never heard a dicky bird from the the guy who bought your kit, reckon he was out of his depth, apparantly he has lent the stuff to a garage

He seemed to have a pretty decent set up and quite a few P38's that he was selling/repairing. Nice workshop with 4 poster lift, plus a full range of Snap On kit, and his own recovery truck, the guys in the next unit to him had a body shop and whilst I was there, they had done a great paint job on a P38 for him...all in all, he had the potential for a successful business. He is a decent guy and I hope things haven't gone bad for him as independents in Scotland are few & far between.

Hi

You're not alone. I'm similar in a relative new comer to the P38 and just replaced discs and pads all round - I'll be towing a lot and want to know I can stop.

A few experiences if mine are anything to go by - they were f**ked .

I found a half decent set of 12 point sockets in Machinemart for about £2, a good investment. Whilst there get a set of rounded bolt extractors, a BIG hammer and make sure you have a very long bar to put on the sockets The caliper bolts on the rears are a different size for mine - 19mm front, 17mm back if I remembet correctly.

The caliper to holder bolts came off relatively easily, when that big bar is applied but swing room is limited on axle stands. The sliding bolts wouldn't partly because a previous miscreant had shredded most of them. I got correctly sized slider bolts included with front pads (mintex pads) - but only one for each side. The back ones had the wrong size - so buy some of those as well!

Needless to say on each caliper at least one slider was seized so get a repair kit for them - it doesn't cost much. it's four (2 x caliper) slider pins and some grease for each axle in a pack.

Also be prepared to either rebuild the calipers or replace. On mine the rubber had either ripped or was very close to doing so. I picked up new calipers for around £30 a corner (I think refurb kits are about £8 but from experience on other cars can be a sod to get seated properly whilst sitting on a driveway).

With the brake discs the easy bit was the screw - it's a pozidrive - and came out after 2 or 3 swift blows on the impact driver. Unfortunately the discs themselves where bordering being seized on the hub. Blows with that big hammer on alternate sides (spin the hubs if you can) freed them but it took a lot more than I expected until there was some movement.

If you are using original calipers get a good sized g clamp to press the pistons back in.

Putting it together again is straightforward.

The final step is to bleed the system - look this up in RAVE as there is a specific sequence to bleed the ABS unit and calipers. If you don't do it that way it won't work, trust me I had to go read the book and do it again right

I would suggest you get everything up front assuming the worst - I got sale or return from local specialist supplier - or have easy access to a local well stocked factor.

I only did mine week before last so it's fresh in memory if you get stuck on anything.

Wow, cheers Trevt. That was pretty comprehensive!

I've had some other issues so the brakes got put to one side. Mine aren't too bad, I just like to replace everything like that when I first get the car so I've room to take my time and then I know it is all done and I can relax for a bit.

Assuming I get the central locking fixed and the air-con valve working properly the brakes will be next!

J