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Joined: Jan 15 2016
Posts: 370

Just finished the brake modulator overhaul and modification as supplied by Range Rover Solutions in Australia. I have no intention of trying to usurp Russell Botha's excellent and detailed instructions, but here's a couple of things I found along the way. Remember I'm a left hooker, some of this will be easier/different on a RHD.

First thing is that Russell recommends having the suspension at standard height to make later bleeding easier. If you are 7'13" this may be an option. I pulled the ABS relays and fuses and dropped to access. I can run it back to standard without firing up the pump later.

The modulator is big. It's big and it's awkward. Do your best to get as much fluid out as possible. Disconnecting the line between the pump and reservoir at the res end was easiest for me. I put plenty of rags underneath to catch errant drips when you start to undo the hard lines.

Once out, you drift the pins that hold the fork in giving you this little lot...

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Then you attack the modulator from the other side. So far everything went swimmingly and as per the book, until it came to remove this...

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I had to use some of this...

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I was careful to heat the plug rather than the surrounding alloy. It needed 4 or five heat/cool cycles before finally letting go. You can probably see why...

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I could then drift out the gizzards from the other end. A 1/4 drive extension bar is ideal for this as it sits squarely on the end of the cylinder to be drifted, with zero chance of internal damage.

The little filter is a tad tight. I went gently all the way around, applying tiny pressure only, like this...

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This is what all the fuss is about...

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Mine were in one piece but very easily broken for removal. Getting pretty brittle, I'd say.

New ones fitted up no problem...

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Then it was time for o-rings...

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There's seven. I could only find homes for six!

Hiding in the end of this...

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You can see it in the instructions photo. It looks a bit like a cartridge firing cap, is this...

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Just drift it out from behind and this is where your 7th o-ring lives! It seems to have no purpose than as a blanking piece. I dunno? Anyway.

Reassembly is very straightforward, giving you this...

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Then the fun starts. Getting the pig back in. There's no pictures of this. I haven't got enough hands.

Russell gives you the choice of bench fitting the reservoir or leaving it until the modulator is in. On a left hooker, leave it off.

As you look at the modulator in the vehicle from the front, there are three hard lines on the left, two at rear bottom, up by the bulkhead, one towards the front, three on the front and a single one, with banjo fitting on the right side.

On a RHD vehicle, the first three lines, on the left, will be towards the wing and access should be fairly good. On LHD, someone put an engine in the way and they are a bastard! Especially the two bottom ones. To start with I tried to fit these before locating the modulator, trying to make access easier. Don't bother. The rearmost, which on mine, feeds the front LH caliper, runs underneath the modulator and with that loose, it's impossible to get the right angle on the pipe with a very real risk of crossing the thread. Fit the mod up, break four fingers on your left had and get stuck in there. You'll get at least a 5 degree turn on the spanner every time and it only takes an age, so get on with it. This is one of the reasons I recommend access height. I was already stood on points like a bloody ballerina as it was.

Once you've got these two on, the rest are pretty straightforwards. Once you've done, refit the reservoir. A smear of brake fluid on the rubber bungs and steady pressure worked for me.

Amazingly, the fork slotted happily over the pedal and travel is nice and smooth.

So it's in, all connected up, which brings me to a question. The instructions tell me to pull the plunger on the brake switch out, push the pedal in slightly and refit. Mine doesn't want to come out at all. I seem to remember somewhere about the very early ones (mines January 1995 build) not being the same. Can anyone shed some light?

Apart from that, I'm still waiting on the hoses (which are somewhere in the Philippines) and I can get some fluid in there and see if it all works.

Apart from the plastic washers looking on their last legs, some of the o-rings weren't particularly pretty, so I'm glad I got in there and replaced them all. Interestingly, my modulator is dated 1997 on a 1995 vehicle and Nanocom tells me I have 4 wheel traction control. Ah well.

Once again, top instructions from Russell, the actual job itself really isn't difficult.

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Joined: Dec 29 2015
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I guess that plug was held in with some sort of loctite? What did you stick it back in with?

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Joined: Jan 15 2016
Posts: 370

Some goo I got here in the "Gluey Stuff" section of a hardware shop. It's just called Threadlock Blue.

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Joined: Dec 29 2015
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Hmm, I wonder if it's worth organising a group buy of these kits? How much was it?

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Joined: Jan 06 2016
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When I bought mine in Jan 2016 it was AUD 165 inc postage, which is around £103.00 at todays exchange rate.

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Joined: Dec 30 2015
Posts: 1086

I'm in the middle of stripping/rebuilding a modulator for my '01. It has the stainless steel parts already, but the rest of it was looking a bit gross... that little filter on mine was pretty well caked up with something really fine.

I'm buying the O-rings locally in the UK (as I don't need the whole kit at the moment) - but think I've got some of them a bit wrong...

I don't suppose one of you guys with the kit and a digital caliper would be able to measure the width of the rubber part of the O-ring for the 3 which go on the bit with the filter? I thought they were 1.5mm, but having fitted them to that unit, I'm not thinking they are a bit bigger.. I measured the groove they sit in at about 2mm, but wouldn't mind a second opinion before I go and put it all back together!

If there is a group buy option at some point, then put me down for one of the kits, as I'll need one at some point for my '98 restoration P38... it's definitely one of the things I want to upgrade!

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Joined: Jan 06 2016
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If I can find the kit in my parts warehouse (!), I'll measure the o rings...
EDIT- can't find them at the moment. I've "archived" all my GEMS spares into deeper storage, but will keep looking...

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Joined: Mar 12 2016
Posts: 647

At least you've made it to a sticky George!

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Joined: Jan 15 2016
Posts: 370

Orangebean wrote:

When I bought mine in Jan 2016 it was AUD 165 inc postage, which is around £103.00 at todays exchange rate.

This sounds about right.

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Joined: Jan 15 2016
Posts: 370

Martyuk wrote:

I don't suppose one of you guys with the kit and a digital caliper would be able to measure the width of the rubber part of the O-ring for the 3 which go on the bit with the filter? I thought they were 1.5mm, but having fitted them to that unit, I'm not thinking they are a bit bigger.. I measured the groove they sit in at about 2mm, but wouldn't mind a second opinion before I go and put it all back together!

Damn, three days ago,the answer would have been yes!

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Joined: Jan 15 2016
Posts: 370

Ferryman wrote:

At least you've made it to a sticky George!

Infamy at last!

As I said, the instructions were very good and easy to follow, but as most of us won't be doing this on a daily basis, I thought it was worth telling what I found to be easiest. Or should that be hardest? Especially for those who are LHD as well.

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Joined: Jan 15 2016
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gordonjcp wrote:

Hmm, I wonder if it's worth organising a group buy of these kits? How much was it?

I pointed Russell towards the site in an e-mail yesterday, so he may pop in?

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Joined: Jan 06 2016
Posts: 2312

O ring measurements as attached pic Marty
All are as good as I can get with a vernier, as I don't have an O ring gauge
enter image description here

Martyuk wrote:

I don't suppose one of you guys with the kit and a digital caliper would be able to measure the width of the rubber part of the O-ring for the 3 which go on the bit with the filter? I thought they were 1.5mm, but having fitted them to that unit, I'm not thinking they are a bit bigger.. I measured the groove they sit in at about 2mm, but wouldn't mind a second opinion before I go and put it all back together!

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Joined: Dec 30 2015
Posts: 1086

Thanks for that - that's pretty close to what I had worked out already - it was just the 3 middle ones I had as 1.5mm, but looks like they are a little bit bigger than that, which was my suspicion when I fitted them. Looks like I've got some new ones to order!

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Joined: Jan 15 2016
Posts: 370

A teensy update as I was thinking about stuff, which is often a bad thing...

You'll remember that all this gubbins here...

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Is located by this here plug...

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As you can see,there's an internal step and the end is open. No doubt this has contributed to the rust and crap you can see.

So...

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I found a little plastic bung, popped a small breather hole in it and stuck it in the end of the plug.

Will it help in a future dismantling? No idea!

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Joined: Dec 30 2015
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Idly looking at things under the bonnet, I noticed that the big hex key plug is right at the front of the modulator which made me think (which is always a bad thing). If the springy thing with the plastic bits that break up lives behind that, couldn't it be done with the unit still in the car? At least it would be bolted to something solid when giving it some grunt rather than having to chase it round the workbench. Also, do the plastic bits only exist on earlier cars or all of them and what is the result of them breaking?

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Joined: Jan 06 2016
Posts: 2312

Plastic up to introduction of Thor. Replaced by stainless component.
If they break, worst case total loss of brakes, but in reality, how many cases worldwide?
Many pages of debate/ discussion here
http://www.rangerovers.net/forum/7-range-rover-mark-ii-p38/15632-please-read-all-p38-owners-up-mid-1999-brake-modulators.html
"Clicky" pedal is usually first symptom.

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Hmm, I've just read through that thread and it seems that although the modulator part number changed from the Thor, all the ones that seemed to have the problem were early cars (95-97). I wonder if they changed the washers from plastic to metal partway through production rather than when the newer version was introduced? An internal change wouldn't have warranted a change of part number if they were externally identical and interchangeable. There seemed to be a lot of failures in Oz and George's washers broke when he took them out but hadn't beforehand so I'm wondering if it's a temperature related thing? I don't have a clicky pedal (a squeaky one sometimes but that is down to it being such a bitch to get any oil on the pivot) and if it was mileage related mine should have gone years ago. Has anyone taken one apart and found broken washers?

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Joined: Jan 15 2016
Posts: 370

I also have a question, but I'll do a separate thread, maybe move it here later.

https://rangerovers.pub/topic/449-brake-bleeding-as-per-rave

Anyway, no it can't be done in-situ as the bits with the placcy washers can only be accessed when you remove the pedal fork, and you need to drift two pins to get it out. So you need to get in there as well. Shame...

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Joined: Jan 15 2016
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Now with revitalised picture links!