Front breaks lock up now all sorted passed thanks all

[DAZ]

For those that dont know i have fitted 94 model 80 series diffs under my 82 40 series and all i have to do is sort my breaks and the enginer will give me my ticket and ill be street legal.

The prob i have is the rear breaks lock up and not the front i have the standard 40 master cylinder still that was connected to front disc breaks from the factory and have fitted a brake bias valve out of a hilux to the rear but it has not fixed the prob i thought it should have so i dissconnected the rear breaks and went for a drive and it still wont lock up the front even though the rear is disconnected . Dose the master cylinder from factory have less fluid pressure going to the rear im wondering if the wrong line is going to the wrong end of the car out of the master cylinder ? Any input would be greatly appreciated thanks Darren

[Busiboy]

I can't tell you the answer to your problem but I have the same dilema

I fitted Hilux discs to the front of mine with all the calipers etc from the hilux. Going for a drive it pulls up ok BUT the front doesn't lock up. I really jumped on the brakes the other day I noticed it didn't really pull up that well.

I put it down to having 35's on it but if you sus your problem I will be eagerly watching for your solution.

I am thinking the old 40 master cylinder just doesn't have the grunt to squeeze those calipers properly.

Going to go and re-bleed mine and try again.

[dumbdunce]

For those that dont know i have fitted 94 model 80 series diffs under my 82 40 series and all i have to do is sort my breaks and the enginer will give me my ticket and ill be street legal.

The prob i have is the rear breaks lock up and not the front i have the standard 40 master cylinder still that was connected to front disc breaks from the factory and have fitted a brake bias valve out of a hilux to the rear but it has not fixed the prob i thought it should have so i dissconnected the rear breaks and went for a drive and it still wont lock up the front even though the rear is disconnected . Dose the master cylinder from factory have less fluid pressure going to the rear im wondering if the wrong line is going to the wrong end of the car out of the master cylinder ? Any input would be greatly appreciated thanks Darren

you are probably going to need the 80 series master cylinder to make it balance close to correctly - maybe even a manually adjustable brake proportioning valve. RTA doesn't like them and engineers will usually require them to be fitted in the engine bay (or elsewhere outside the cabin), and to be wired/otherwise sealed so they cannot be adjusted after the engineer has performed his brake testing.

with the rear disconnected however, the fronts should lock up easily, 80 series brakes are huge.

you can fiddle with the brake bias a little by using different brake lining materials front/rear.

cheers

[DAZ]

ive got 33's and tryed rebleeding over and over going to swap the lines from front to rear tonight and try that

what better master cylinder will bolt up to it mabey 80?????? help

[dumbdunce]

ive got 33's and tryed rebleeding over and over going to swap the lines from front to rear tonight and try that

what better master cylinder will bolt up to it mabey 80?????? help

not sure if the 80 master cyl will bolt up, but someone will know. stocker tyres on 80s are 32" and lock up easily so something is wrong somewhere. I don't think swapping the lines is the answer man.

[DAZ]

Dose any one know if the 40 master cylinder puts out more fluid/pressure out one line compared to other.

I have fitted a proportioning valve out of a hilux in the rear break lines similar to what is in the rear of an 80 that should help with break bias plus HQ apparently have a inline valve under the drivers door that reduces the fluid going to rear breaks by 30% i might have to try and get one of them not much point till im able to lock up the front breaks though. Any thoughts any one

[Mytqik]

The drama here is that the 40 came out with drum rears & the 80 had discs.

I know you mentioned you put a hilux bias valve under the rear, but the hilux also had rear drums brakes. Therefore this bias valve will be set up for letting the correct volume of fluid through for a drum brake setup, not discs.

You will need the master cylinder & brake booster of a 80's cruiser, as this is designed to flow correctly for your calipers. (I would have thought this would have been one of the engineer's requirements)

[MissDrew]

Daz go out and have a look at the master cyl on your 80, if the 4 bolts holding it on are the same distance apart as the 40 then it will bolt up, I have 80 mc on the lux. A brand new 80 series mc is no more then $120, you are welcome to BORROW the MC off my lux and try it before buying one if ya want, I want be needed it for awhile


Oh and have a look on the side of the 40 mc and see if you can read what size it is, the 80 has a 1 inch bore, hilux was a bit under 1 inch. But at the same time the bigger bore of the mc will mainly only help with pedal pressor not so much the braking, the brake booster however will help alot more with that. This is how a brake joint explained it all to me, wheather thats correct or not I don`t know.

PS I haven`t picked up stuff from sisters yet and I`m going to get chris to do that bill out, will look better then being from brother

[Mytqik]

The only purpose of the brake booster is to assist with pedal pressure. The booster relies on vacum form the engine or vacum pump, which creates a negative pressure within the booster & this negative pressure assists you to apply the brakes via the pedal.

Your brakes will still work if your booster or vacum supply fails, however it will be *ALOT* harder to push the pedal in. The booster in no ways dictates the direction or volume of the fluid flow. This is the job of the MC.

The master cylinder bore dictates the volume of fluid that will flow for a certain pedal movement. That is why people increase the size of their MC, as it can greatly reduce the pedal distance.

I have found that most toyos use the same booster from asian, so if your booster has the 4 bolts like GUTS says, then you should be able to swap the MC between the two vehicles.

This should greatly increase the volume flowing to your front brakes & allow them to lock up.

[MissDrew]

I was close, just around the wrong way not to bad for somebody that knows fark all about motors and brakes in the way that they work and was told about them about 2 years ago while not realy listening

[V8 Middy]

I'm having similar dilemmas on the Middy. The rears will just lock up butt not the front. The braking was bad on 31's and now really crap on 35's. Got new bendix 4wd pads and rotors machined made a difference but would have thought 4-pot cailpers could do better than that.

[DAZ]

The drama here is that the 40 came out with drum rears & the 80 had discs.

I know you mentioned you put a hilux bias valve under the rear, but the hilux also had rear drums brakes. Therefore this bias valve will be set up for letting the correct volume of fluid through for a drum brake setup, not discs.

You will need the master cylinder & brake booster of a 80's cruiser, as this is designed to flow correctly for your calipers. (I would have thought this would have been one of the engineer's requirements)

thanks for feed back people

now the 80 i drive to work each day that i didnt even think to look at master cylinder of has a break bias valve on the rear that looks similar to the one i just fitted on the 40

my question at this stage is dose a drum break or disc break require more fluid ?(if the disc requires more shouldnt the prob be my rear breaks not front?)
and dose the standard 40 master cylinder put out more fluid out of one line than the other
The break pedel dose not have to move a lot in travel to lock rear breaks nor dose it have to move much to work on front just wont lock them no matter how hard i push
tonight i am going to swap the line from front to rear nothing to lose then Guts i will prob take you up on borrowing the master cylinder if it will bolt up good one thanks (and i need bill asap i have the others thanks)

[DAZ]

I can't tell you the answer to your problem but I have the same dilema

I fitted Hilux discs to the front of mine with all the calipers etc from the hilux. Going for a drive it pulls up ok BUT the front doesn't lock up. I really jumped on the brakes the other day I noticed it didn't really pull up that well.

I put it down to having 35's on it but if you sus your problem I will be eagerly watching for your solution.

I am thinking the old 40 master cylinder just doesn't have the grunt to squeeze those calipers properly.

Going to go and re-bleed mine and try again.

I am guessing your truck had drumbs on front origionaly (mine had discs orig) so your prob should be the wrong master cylinder as mine might end up being that as well if i remove mine and get another you can try mine if you wish

[Busiboy]

That would be great if it fixs the problem.

Like Middy though I generally have a poor braking issue with no locking up and I think this is mainly due to 35's. I am sure some of these little things could all add up though and am willing to try anything.

[Zeyphly]

I was told that putting frount discs of 40 series the thing to use was a sixty series mastercylinder and booster. O havent got around to trying it out but it may be an option

[Zeyphly]

I was told that putting frount discs of 40 series the thing to use was a sixty series mastercylinder and booster. O havent got around to trying it out but it may be an option

[DAZ]

I went to ABS and they said trial and error with veichaels like this this is what i have

oh and i bought some new pads for the front they sujested they might be hard and not sticky enough

[DAZ]

apparently the standard veichael has a proporitioning valve fitted standard that is what is under master cylinder here is a photo of the load share proportioning valve i fitted

[DAZ]

swaped lines front to rear made no differents far out what is it ABS did also say dont recon master cylinder off 80 will make much difference?

[Busiboy]

I can't see anthing but the master cylinder being the problem.

Not much else in the equation.

[skootin]

From the picture of the load prportioning it looks as if it is in the loaded postion which is giving a lot of pressure to the rear .The arm should be adjusted.IF you got 80ser brakes frt and rear it would make sense to use the master cyl desinged to operate the. It will bolt to the booster.

[DAZ]

Fa$%k it ive bit the bullet i am ordering the 80 master cylinder on Monday fiiting new front break pads and seeing what happens from there thanks will update

[Busiboy]

Daz, you tried fiddling with the load proportioning valve didn't you?

Still trying to get mine running so don't need brakes yet.

[J Top]

The answer on a 40 is to fit a second , remote ,booster in the front brake line, ie; off a Hillman Hunter or a Tasman/Kimberley/1800 etc.
The drum brakes are self engergising by design so require less force to lock.
The discs need more pressure, the M/C change may do it , I have never tryed it, but have fitted many remote boosters.
They are getting harder to find now and may need an overhaul before fitting.
Fitting a proportioning valve reduces your rears which doesn't really help the fronts.
J Top

[MissDrew]

His 40 had disks on the front before he put the 80 diffs under it.

He has even gone to the point of clamping the rear brakes so that they don`t work and then tried to get the front to lock up, they still won`t lock up.

[J Top]

Increase the Boost, it has worked the 10n or so times I have done it.
J Top

[DAZ]

thanks all i have ordered parts will be fitted b4 week is out then i will update on progress or regress

[80UTE]

Ive just come back from holidays in WA and saw this post. With 80 mastre cylinders there are 2 bolt mounting and 4 bolt mounting i would sugest fitting the 80 booster as well as they are a dual diaphragm design and realy help with brake performance. To have some hope of getting it right it is good practice to fit the all brakes components (brakes front and rear, booster, mastercylinder and proportioning system) from the same donor vehicle. The 80 booster c/w master cyl will bolt up to the 40 firewall but the clevis that attaches to the pedal needs to be longer to connect up and put the pedal in the right spot.

Wally

[DAZ]

Ive just come back from holidays in WA and saw this post. With 80 mastre cylinders there are 2 bolt mounting and 4 bolt mounting i would sugest fitting the 80 booster as well as they are a dual diaphragm design and realy help with brake performance. To have some hope of getting it right it is good practice to fit the all brakes components (brakes front and rear, booster, mastercylinder and proportioning system) from the same donor vehicle. The 80 booster c/w master cyl will bolt up to the 40 firewall but the clevis that attaches to the pedal needs to be longer to connect up and put the pedal in the right spot.

Wally

hi how is it going Wally thanks dud ive ordered master cylinder now and will fit it and pads and see how it gos i tend to agree with all you have to say but unfortunatly i dont full understand the reaction to each action with the breaks and the guys that are ment to be in the know at ABS where of no help i guess the joys of bulding trucks

parts are in in morning and fitting tomorrow night

has any one got a 80 boster lying around and how$ thanks again all Darren

[DAZ]

master cylinder did not turn up wont be in till Thurs now they say