Thread: Disc Brake Conversion.

I also need to know about the proportioning valve as i already have one fitted as i fitted duel circut brakes from a later model all engineered , I have been told the the valve is a safety one in that if the front fail the rear still works & if the rear fail the front still work.. I was also told the valve puts more brake presure to the front than the back .
So i'm wondering if its ok to use it with discs on the front & if its ok to use when i put discs on the rear no one seems to be able to tell me any differant they say it can be use with drum brakes or disc brakes, so any advise on that would be great..

This is what i asked the engineer about the proportioning valve..

& this is the one i have fitted . . .











I was told it was from a stage 1 series3 V8. i brought the booster, Master cylinder & prop valve from Gary CLR off ebay he is from around Sydney somewhere from memery..

That looks like a junction connection, the one you need to fit is from a disco its so you don't lock up the brakes when stopping (has a set ratio of pressure)

Will take pic tonight

Adam

I think its called a brake pressure relief valve but will take pic tonight

Adam

Originally Posted by agrojnr

I think its called a brake pressure relief valve but will take pic tonight

Adam

Actually it is a brake balance valve, the last thing you would want to do is relieve pressure in the braking system.

The function of the valve is to mechanically detect loss of pressure in one system, when one side is low a shuttle moves from the high side to low side, operating a switch that is usually connected to a warning light on the instrument panel.

AFAIK a proportioning valve is usually connected in line near the rear suspension with a mechanical connection to the rear end detecting the suspension compression. They reduce the pressure to the rear end when there is no load on the tray. Usually found on load carrying vehicles like utes and traybacks and 101 land rovers.

Originally Posted by Lotz-A-Landies

Actually it is a brake balance valve, the last thing you would want to do is relieve pressure in the braking system.

The function of the valve is to mechanically detect loss of pressure in one system, when one side is low a shuttle moves from the high side to low side, operating a switch that is usually connected to a warning light on the instrument panel.

AFAIK a proportioning valve is usually connected in line near the rear suspension with a mechanical connection to the rear end detecting the suspension compression. They reduce the pressure to the rear end when there is no load on the tray. Usually found on load carrying vehicles like utes and traybacks and 101 land rovers.

Yep thats what mine is...I had to put a light on the dash & a wire goes from it to the valve..
But I was told by an engineer a few years ago now that the front wheels have to lock before the rears..So now i am getting a bit confused . .

And if your brakes don't lockup at all would you get surfishent braking though ??????

So i have to change mine to put discs on the front but still have drums on the rear..

And when i want to put discs on the rear does this mean i have to change it again..

Do disco's have drum rears at all or are they all discs allround ????

And what does this meen i have seen people use it a bit now but have know idea AFAIK .

Don't worry its just the idiot in me trying to work stuff out......

Originally Posted by banjo

Yep thats what mine is...I had to put a light on the dash & a wire goes from it to the valve..
But I was told by an engineer a few years ago now that the front wheels have to lock before the rears..So now i am getting a bit confused . .

And if your brakes don't lockup at all would you get surfishent braking though ?????? Yes and no if you go over the pits then they will say no

So i have to change mine to put discs on the front but still have drums on the rear.. No if you just put disc's on the front

And when i want to put discs on the rear does this mean i have to change it again.. Yes

Do disco's have drum rears at all or are they all discs allround ???? Disc all round

And what does this meen i have seen people use it a bit now but have know idea AFAIK . No idea

Don't worry its just the idiot in me trying to work stuff out......

Adam

AFAIK = As Far As I Know. (same as I believe) Usually meaning that the poster is not 100% sure of the fact.

Disk brakes and drum brakes work with different valves in the master cylinder.

In a drum brake system the shoes are held off the drum by springs and the adjusters prevent the shoes pushing the pistons all the way back into the cylinders.

In a disk brake system there is some residual pressure left in the system keeping the piston/brake pad close to the rotor.

Yes you need different master cylinders for:

• drum brakes front and rear (series models - have both single and dual circuit systems).
• Disk front & Drum rear. (110 and County models)
• Disk front & Rear. (Defender models)

Although good brake service professionals may be able to fit the correct valves in the master cylinder your vehicle already has, so long as it's a dual circuit.

Tried the bracket today....it fits perfectly, well done Adam! The quality is excellent, it looks and feels strong enough to do the task, but will no doubt still require an engineer to verify.

The two caliper bolts are Metric 12mm x 1.75mm x 30mm. I tapped the bracket pre cut caliper holes out. The recommend drill size for that tap is 10.2mm.

It's tight to get the lower caliper bolt in, but it fits (same as the original bracket)(See photo marked in yellow).

I can still see no reason why the original bracket has a chamfer in the edge (circled in photo in green).

It looks as though there may be no need to have a spacer, the bottom edge of the bracket is where the caliper bolts to, so whatever we lost on the top has not changed the fit. As with the original bracket I had to fit a 3mm washer inbetween to make the caliper sit at an even height on the disc.

The disc is fitted to the underside of the hub with 6 Metric 10mm x 25mm bolts. I have removed the 12oclock and 2oclock bolts for the rear photo.

I also pulled apart my Discovery wreck rears today, the pads and calipers are the same, but the discs are deeper and will not fit.

Series III 272309 Rims will not fit. Discovery 1 Rims will fit with a 5mm wheel spacer.

Part Numbers:

Caliper - LOCKHEED 3242 292C L8 PQ (IDENTICAL TO DISCOVERY REARS)

Disc - 11 93 E BB MIN TH 11.5 MM NB 93 (NOT DISCOVERY REARS)

Pads - AP LOCKHEED 5867A1R8 M (IDENTICAL TO DISCOVERY REARS)
or APEC TYP 8823 PAD 582 1 OD23