Roctoy Brakes

[Winklux]

Hey

I've been trying to get the roctoy disc brake conversion working on my ln106 hilux. Its all put together like the instructions from roctoy's website say with the only difference in the master cylinder i used. The instuctions say use a master from a prado, part number jb9527. This part only has 2 holes to mount the thing on the booster while the hilux booster has 4 studs. I found a differnt master, with part number jb1879, from a early '90s four wheel disc 80 series landcrusier that fits. Any way I couldn't get it to work so took it to my mechanic, he fiddled with it for ages and found the main problem being a big gouge in the piston inside the master cylinder. He's put a new master on but now it only seems to have front brakes with a very bad peddle feel. He tells me that when the rears are clamped off it feels fine and stops good.

So today when I got the ute back the brake light was on. There didn't seem to be anything happening that would set off the brakes light. So after some playing around with the resviour cap the little float seemed to be working in reverse, showing continuity with the float at the top of the little rod under the cap if that makes sense.

The mechanic had this idea about making some shims to put behind the pads to move them closer to the disc. I was thinking about doing this but I think he's put the wrong master on.

Any advise about what to do next or what master others have used or any ideas at all would be a real big help.
Thanks heaps

[the_4br]

ive got an 80s master 1inch bore it seems to b alot beter but not as good as i thouhgt it wouuld be

[Winklux]

Ya wouldn't remember what model and year it was from by any chance?

[De-lux]

Have you tried calling Chris (roktoy)?

[UhhOhh]

The brake light is only a resevoir fluid level warning not sure why it would be in reverse.

Is your LSPV in good working order? You may be losing brake pressure through it. Also double check you definitely got the right (4 wheel discs) master as a drum rear master will cause these symptoms.

[Winklux]

The mechanic did find that the lspv was seized, I watched him take it apart and got it moving again but got no idea if it's working properly. I'm gonna see if I can by pass the lspv as soon as I can get to the wreakers to grab some spare lines. Is it as simple as connecting the line from the MC to the one to the back brakes and blocking off the one going back to the front brakes.

I asked he mechanic if was sure the right master got fitted cause they mentioned something about the wrong part got delivered from the parts shop. He said the right one got fitted ( yeah i know like he's gonna say he put the wrong one on). Is there a way to check the part number of the master. The invoice says it's a jb1879p. It says on the side it's a sanco and has a 1 inside a square about a inch to the right. Apart from that it hasn't got any other markings on it that I can see. I dunno if it says anything on the side that faces the booster. I'd put some pictures up put I can't work out how to do it from my iPhone.

[Roctoy]

Hi Tim

Like i said on the phone, it sound's like a process of elimination to find out where the problem actually is. The setup has been used hundreds of times now and there have only been a few people that have reported having problems getting it all working. The common problem is the parts sourced from wreckers etc. Using second hand parts is always a gamble when doing these things, sometimes master cyliders leak, calipers are siezed etc.

Although it isn't advisable to take the load sensing proportioning valve out of the equation, it sound's like that may have contributed to the problem.

Drama is that every time you pull something off you will need to properly bleed all of the air out of the brake system. As frustrating and time consuming as this is, if you short cut it at all you will have no brakes.

Many people have used the non abs 80 series master cylinders or prado master cylinders but the part numbers are alll different depending on wether they are aftermarket, genuine, match the hilux booster, what model hilux they have etc, etc. (you can see why it's hard to quote exactly which master is the correct one) As long as it has a bigger bore than the standard hilux master you should be ok.

Let us know how you go.

cheers Chris

[Frankenyota]

You can fit an adjustable LSPV or remove it completely.
I have removed mine as it leaked again but i have rear drums.
I was going to fit a 60 series proportioning valve but have not got around to it yet.
The brakes are still fine thou.

Matt

[Winklux]

I went and got some stuff I'd need to by pass the lspv. Hopefully it stops raining tomorrow so incan get on with it.

Anyways can anybody confirm what model and year 80 series is front and rear disc, without abs. If it's not the lsvp the only thing else I can think of is it being the wrong master.

Also just makin sure with the subaru calipers, I got the bleeder nipple below where the hose connects. Is that right? I know that isn't normal but it's the way it is in all the pictures i could find, and I'm pretty sure that's the way they were on the subi when I pulled them off, and it seemed that it wouldn't fit on the diff houseing any other way.

[turbo gu]

The blled nipples need to be the high point. If you have the brake line above the nipple you will never be able to bleed the brakes. If they dont fit anyother way lift the caliper up so the nipple is higher than the hose then gravity bleed the brakes then fit them back up

[Frankenyota]

You need to have the bleeders at the top, or do as turbo gu said to bleed it.

Matt

[Winklux]

Alright, I bypassed the lspv and bled the rear brakes with the calipers upside down with a block of wood inbetween the pads and it made no difference. I clamped off the rear again and had good peddle. I didn't test the brakes with the back clamped cause I didn't put the wheels back on.

So it seems that the master isn't right, right.

Also am i right in thinking that if the calipers were seized it would have a hard peddle not one that goes straight to the floor like I got now.

Thanks again
Winks

[Winklux]

Also I forgot to ask before. The mechanic had an idea about making some shims or spacers to go between the pads and the piston. The piston has about 3ish mm showing. I don't think it'll work but I'm no mechanic and I've never really done much if this before, but I dont wanna go spending money for no reason. Just after anyones opinion on that and the what model 80 series master cylinder I might need.

Thanks again
Winks

[RAY185]

The fact you have a good pedal when the rears are blocked off tells me that your master is actually working fine but your problem is in the rear brakes.

If you are confident you've bled all the air out then I'd suggest that perhaps you are using the wrong thickness rotors on the rear, pistons are travelling out too far (you should be able to eye ball this while it's up on jack stands). If this is the case then perhaps your mechanic is onto something with shims but it's not the ideal solution. Correct rotors is.

[Frankenyota]

Problem seems to be with the rear.
Are you using the correct rotors as Ray said?
Not familiar with the subaru calipers but some calipers with a handbrake mechanism also have
an adjustment to wind out the piston to adjust the handbrake.
See if it has a 14mm nut on the back side of the caliper, behind the piston?
Or post a picture.

Matt

[Winklux]

The rotors should be the right ones.
There's no nut on the back of the caliper either, but the piston winds in and out on a long stud inside the bore. Maybe that's what adjusts the piston.

[Roctoy]

http://www.dba.com.au/products/dba622

the rotor width should be 18mm

[Struth]

I find the only way to bleed my system is with a vacuum brake bleeder. Old fashioned push the pedal open the nipple just does not work some times.

[Winklux]

^^ do you have the same set up Struth

[Struth]

Similar, 60 seies diff converted using Subaru calipers and with the standard proportioning valve.

I find vacuum bleeding will give decent pedal retention, then drive for a day or two, bleed again and it gets better, another day or two, bleed a last time and brakes are awesome all round.

I broke a solid brake lin inthe rear when bush on the weekend, replaced the line but there was simply no way I could get pedal retention by manual bleeding. I will vaccum bleed it again today and it should be perfect.

trick is to take the calipers off if required to get the bleed nipple at the top then vacuum bleed only. reposition the calipers on the discs and pump the pedal until you get retention. Rpeat this two or three times until all is good. remember to bleed the propiortioning valve if it has a bleed nipple first.

Don't pump the pedal unless the caliper is on the disc.

my setup,



have plenty of brake fluid and bleed each side liberally to get all the air out.

[Winklux]

Ok cool. When ya take the calipers off to bleed them do ya turn them upside down (like with the hole where the disc goes facing down) or just tilt them a bit.

I ask cause I was looking at a busted subie caliper I had and by the look of it even though the bleed nipple is below the hose connection on the outside the way the things built on the inside it looks like the hole for the bleed nipple is at the top of the bore.

[Struth]

Either rotate it up so that the bleed nipple is at the top or take both bolts out and move it so the nipple is at the top. If you don't get the nipple to the top you will never bleed the air out of the system.

Cheers

[Winklux]

Ok i just got news from the brake specialist. He put a new master on it (one that spoused to be from a rear disc non abs 80) and it still doesnt work. He's telling me ya need to pump it up to make the rears work and jinks it either needs a bigger master or smaller pistons in the rear. But he's alsO of the opinion that if it went bigger master the front would come on too hard. So my question is are there different sizes of subaru caliper or can any one tell me what is the right master to run.

[Frankenyota]

There was a thread on here about what parts you needed and the difference in calipers.

[UhhOhh]

It's looking like you might have got the wrong calipers there mate. Off Roctoys site it said you need: '88 / 89 L series Subaru calipers part No. ABP3K

Hope you get it sorted anyway mate sounds like you've had enough dramas to last you a while with it.

[Winklux]

Yeah after some more research there are smaller subi calipers but they have the mounting holes closer together so they wouldn't fit on the brackets.

I took the ute for a drive this afternoon. If ya push on the peddle just once ya get almost no brakes but even if ya give one more pump it stops good, and if ya give it another the rear will lock up. So me and the brake guy come up with the idea of a valve that would keep a bit of pressure in the rear.

Any thoughts on that?

[Struth]

Sounds like a bandaid fix to me, plenty of people run Suby calipers off of Toyota 1" masters and they work fine.
Keep looking for the solution.

Have you had the system vacuum bled yet??

[Roctoy]

have you put new pads in?

are there already thin metal shims in between the pads and the pistons? If there are, make sure they are flat and not bent because this can also cause the problem you are talking about.
cheers Chris