Rear Disk Conversion for the Lemon

Jafa · Post by **Jafa** » Wed May 24, 2006 9:18 am

FJ-80 Master Cylinder
The stock Hilux and Ithink Surf is tha same, master cylinder are designed for discs brakes up front and drums in the rear. It does not have a residual valve for use with rear disc brakes. Without a rear residual valve in the system the rear disc pads move away from teh disc after braking. This causes excess peddle travel the next time you step on the brakes. To solve this use a FJ80 brake master cylinder that is equipped with two residual valves, one for the front system and one for the rear. It's 1" bore size is larger than older 13/16" bore cylinders for more fluid volume, and bolts straight in

SupraLux · Post by **SupraLux** » Wed May 24, 2006 9:37 am

The 80-series master cylinder is a good option... I have one I was going to use in my project d-cab but never got round to doing it in the end... bloody expensive tho. Brand spanking new one - will sell it for $180 if anyone wants it.

As Jafa said, the residual valve is the important bit... as the pads heat up they get further and further away after each braking manouvre and so the more you need em, the less they feel like they are working...

Steve

Rangielux · Post by **Rangielux** » Wed May 24, 2006 11:27 am

Jafa wrote:FJ80 brake master cylinder that is equipped with two residual valves, one for the front system and one for the rear. It's 1" bore size is larger than older 13/16" bore cylinders for more fluid volume, and bolts straight in

Cool, easy as

Thanks guys.

I'm just well happy to be rid of that drum brake headache. 3 muddy bush trips, or across and back over Thompson's and the h/brake would be usless and the pedal would be crap too :roll:

De-Ranged · Post by **De-Ranged** » Wed May 24, 2006 5:31 pm

The volume is similar between the drum and the disk pistons so there shouldn't be any issues.... (for the maxima disks)

I'm gona have to sort something a bit bigger for my disks as I'm a 4 pot :twisted:

haven't worried to much about the master yet ..... found the americans use the surf one as its a bit bigger than the Lux one

Cheers Reece

Rangielux · Post by **Rangielux** » Wed May 24, 2006 7:40 pm

I'll let you know how it works out with the standard master cyl. I have been aware tho that rear discs doo need a residual valve. Watch this space.

By the way thanks for the loan of your thread DR

Looking forward to seeing what else has being going on with the Lemon tho ?

De-Ranged · Post by **De-Ranged** » Wed May 24, 2006 10:19 pm

Sweet good to see a tidy finish to it

as for the lemon, soon :roll:

seems like I've been saying that for some time now :lol:

just sorting a few bits and pieces...

Cheers Reece

NFORCA · Post by **NFORCA** » Thu Jul 27, 2006 12:19 am

Stupid question. I presume you guys are using Maxima discs with the Maxima calipers?

Cheers

MATT4U · Post by **MATT4U** » Thu Jul 27, 2006 12:31 am

hilux front disks

Mattman · Post by **Mattman** » Sun Aug 13, 2006 5:52 pm

Whats needed brake hose wise to connect the cailpers to the rear setup?

Does the load based proportioning valve remain?

Cheers
Matt.

ruf_zuki · Post by **ruf_zuki** » Sun Aug 13, 2006 7:32 pm

correct me if im wrong but the brake lines should be the same thread just carefully bend them, and the prop valve can be left in or taken out, im getting rid of mine coz it will interfere with my shock mounts

oldblue · Post by **oldblue** » Sun Aug 13, 2006 8:39 pm

Back when you could not get disc brakes for L/Cs, i was casting and machineing disc converstions. I always removed the propostion valve that supplyed oil to the front discs. This prevented the piston from haveing a slight pressure on the pads. They seamed to work spot on. Looks like I was wrong in doing this. Judgeing by the earlier info.

Ben · Post by **Ben** » Sun Aug 13, 2006 10:01 pm

I think oldblue is correct, and you guys may have your wires crossed. I'm pretty sure drums use a residual pressure valve to stop the return springs pulling the shoes back in.

Found this too:
http://www.ih8mud.com/tech/residvalve.php

Ben

oldblue · Post by **oldblue** » Sun Aug 13, 2006 10:21 pm

Thanks Ben,
I was hopeing someone would back me up.The valve is there to keep the cup seals pressured .and expanded , other wise they may leak.

DJ · Post by DJ » Sun Aug 13, 2006 10:57 pm

.The valve is there to keep the cup seals pressured .and expanded , other wise they may leak

and its far easier to buy a supra master cylinder as they bolt up the same as a Hilux and are the correct bore size. If the sizes are not corect you can end up in a pile of poo. eg..( in very simple terms )
Large bore size on master cylinder = slow brakes but greater holding power
Small bore size = fast brakes but less holding strength
A small varation in bore size will make a difference as its really the piston area that matters along with stroke etc etc.

rokhound · Post by **rokhound** » Mon Aug 14, 2006 8:13 am

Has anyone doen the Subaru front caliper conversion on the rear of the lux?

If so, what master cylinder did you use?

I have vented lux/crusier discs that have been skimed too 18mm thick (too match the sub standard discs) and an "86 Crown master (from 6m donor car). The master is 15/16. which seemsto be a decent size, but I can't get the pedal to work near the the top. ie it travels way too far.

Would a 1" bore master be the go or not ?

The sub calipers have a decent size pot ( about 50mm daiameter) so I,m guessing that a decent master will be needed. But if anuone else has this conversion running could you please let me know what master did you use?
Cheers guys.

Rangielux · Post by **Rangielux** » Mon Aug 14, 2006 8:40 am

The maxima conversion is still working real good on the standard master cyl. so far

I think because the maxima caliper has only one small piston along with the handbrake being in built (keeping the piston from retracting too much) the master has enough volume to make it work ok. If a caliper with more than one piston or larger volume then the master would struggle I think.

I've removed the load sensing proportioning valve also. Drum brakes in good condition have more brute force than discs so excessive lockups aren't an issue after a disc conversion (especially with a smaller type of disc caliper)

Note: both conversions I've done are on trailered trucks, not road trucks.

oldblue · Post by **oldblue** » Mon Aug 14, 2006 9:43 am

Just a little thiny, If your only replaceing the drums on the front axle ,with disc's , you'll need to fit an (inline Brake proportioning valve). On the rear brake line.Only.

I used to fit HQ Holden one's. This helps to progresivly reduce the line pressure to the rear drums, Helps to reduce rear brake lockup.

Don't confuse a Load Proporstion Valve with a Brake Proporstioning Valve.

oldblue · Post by **oldblue** » Mon Aug 14, 2006 9:57 am

--------------------------------------------------------------------------------

Back when you could not get disc brakes for L/Cs, i was casting and machineing disc converstions. I always removed the propostion valve that supplyed oil to the front discs. This prevented the piston from haveing a slight pressure on the pads. They seamed to work spot on. Looks like I was wrong in doing this. Judgeing by the earlier info.

Remove the word : proposrtion valve and read it as Residual valve.

NFORCA · Post by **NFORCA** » Fri Aug 25, 2006 6:54 pm

I now have a set of Maxima callipers for sale. They wont work on my truck (my other truck - see "other projects" thread)

$20 if any one wants them, including freight nationwide.

What other callipers have people used? preferably something that sits closer to the face of the wheel, as the maxima ones went too far back for my purpose.

cheers

Rangielux · Post by **Rangielux** » Sat Aug 26, 2006 7:55 pm

NFORCA - If they're not gone, I'll have them.
Check your pm

Crash bandicoot · Post by **Crash bandicoot** » Thu May 23, 2013 8:25 am

NFORCA wrote:I now have a set of Maxima callipers for sale. They wont work on my truck (my other truck - see "other projects" thread)

$20 if any one wants them, including freight nationwide.

What other callipers have people used? preferably something that sits closer to the face of the wheel, as the maxima ones went too far back for my purpose.

cheers

I don't know if the axle assembly between the 2wd and 4wd LN56/Rn56(1985) toyota hilux are the same but I used Subaru Legacy brake calipers as they are the same brand toyota used on the front at the time. (asin) from memory i think.
also used ford falcon rotors.

Jafa · Post by **Jafa** » Thu May 23, 2013 8:51 am

Holy thread resurrection Batman! :lol:

Heath · Post by **Heath** » Thu May 23, 2013 6:35 pm

Jafa wrote:Holy thread resurrection Batman!

Grave diggers!!!

Rear Disk Conversion for the Lemon

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Re: Rear Disk Conversion for the Lemon

Re: Rear Disk Conversion for the Lemon