feeling stupid

[loosecanon]

Ok, I feel really dumb about now,

I can't get a brake peddle in my 45 series, I had the twin brake cylinder in the rear, I know how much of a pain in the arse they can be so after some hassle with it I rebuilt a spare I had in the back ( single wheel cylinder). I thought this would fix the problem.

But no luck. Every thing is new, from the booster down to the wheel cylinders. But I can't get a solid peddle. I have bleed the brakes until I'm blue in the face.
I seem to have a nice peddle with the car turned off but as soon as I start the car and get vacuum to the booster she goes soft. I am running out of idea's.

Everything has been adjusted and bleed ect ect. I have found it seems to be the rear though. I worked this out by clamping the rear off and the peddle feels good. Any ideas or tricks will be good,

cheers in advance.

[SIMMO84]

Make sure the bleeders are at the top, ie you haven't got left and right mixed up.

[Struth]

And use a vacuum bleeder, the old push the pedal method isn't real good sometimes.

[loosecanon]

I am now on the single wheel cyclinder's, and yea they are in the right way, had a play with them today. No luck yet.

I did see in the General tech last night about the home built pressure bleeder, Ill give that a go this week.
Any other ideas keep them coming.

[pcman]

clamp all the flex lines and see if you have a pedal , then remove 1 by 1 to determine if its 1 wheel/axle

[howsie]

My cruiser is similar atm. Thinking its because the lspv wasn't adjusted to suit the lift (load sensing proportional valve). Seems pedal was fine after bleeding front at master cylinder but went dicky after bleeding back as because my lspv hasn't been moved all my braking is on the front.

Do you have a lift and have you adjusted the lspv. Would be the for st thing id check.

[loosecanon]

I haven't got mine on,
Doing a build up, and don't really need it.
Could this be apart of the problem?

[howsie]

If the other components were designed to.have a lspv in the system its a possibility

[RAY185]

Hang on. Just to clarify, you replaced the old twin wheel cylinder rear drums with singles? How? What master/booster/prop valve did you use (model?). Safe to assume the front has already been converted to discs?

[loosecanon]

Hey Ray,

Yea I swapped out the old twin cylinder for the single. It was a whole diff swap. The master cylinder is an 84 model, so it meant to suit the single cylinder rear diff.
Yes I have the front disc as well this also came out to of the doner cruiser ( 84)

[RAY185]

What about the booster? Is that off the 84 model too?

[loosecanon]

Sure is. Sounds like you having a light bulb moment Ray. all hope is on you now,

[RAY185]

Haha, no, I really have no idea. I just like asking questions......

How much free travel would you say you have at the top of the brake pedal? So move the pedal (by hand) from the very top down to when you start to feel resistance. Should be about 5mm or so.

I was suspecting bad pushrod adjustment between master and booster but that is unlikely if you used the master and booster from a working vehicle. Still possible though.

If it's not that AND you are sure you have adjusted rear brakes properly AND you are sure there is no air left in the system I'd be looking at the master. Not the first time a "New" master has failed.

[loosecanon]

Gee Ray you had my hopes up.....

Yea I do a lot of stupid things, but i try to limit to only once. I have check it is all adjusted at least twice....

[loosecanon]

Im going to try the pressure bleed system I saw in General Tech.
Any tips on adjusting the booster?

[SIMMO84]

What happens if you adjust the breaks up tight? Hard pedal? You should be able to hear the shoes dragging but not enough to be able to feel it dragging, if that makes any sence. Another way I've had success is reverse bleeding, you pump fluid in from the bottom. The only way I've really ever needed to bleed brakes ( and clutches) is with gravity. Just crack the nipples and let it do the work for you, if it doesn't come at first give it a few quick pumps and it should go.

[loosecanon]

Not sure what you mean by the doing the peddle up tight. Simmo.

But as to cracking the bleed nipple (hahaha Nipples) and letting it do it itself. Do you do this one at a time? I haven't tried doing it like that yet.

[RAY185]

Any tips on adjusting the booster?

There's nothing to adjust on the booster apart from the push rod between the master and booster. Let me know how much free travel there is at the top of the pedal and I'll explain how to adjust it if needed. Should only be about 5mm free travel which equates to about 1mm free travel at the push rod.

Definately try a good vacuum/pressure bleed first.

[SIMMO84]

Not sure what you mean by the doing the peddle up tight. Simmo.

But as to cracking the bleed nipple (hahaha Nipples) and letting it do it itself. Do you do this one at a time? I haven't tried doing it like that yet.

Adjust the breaks up tight so you can't turn the wheels by hand and then check the pedal. Yeah one at a time furtherest from booster and work your way to the front.

[SIMMO84]

What I'm trying to get at is if you adjust the brakes until there tight and you have a hard pedal then it's an adjustment problem, otherwise if it's still soft it's an air in the fluid problem.

[loosecanon]

Kewl will try that in the morning. See how that goes. I think you will find it's fluid though as the peddle pumps up.
But I will try it and see how it goes,

Keep you posted,

Oh and Ray, do you mean just adjusting the peddle height? that would be the push rod that's going in to the booster you are talking about. I wouldn't have thought that would have made much difference, except for the free play in the peddle? I have been known to be wrong before, so please correct me.

[RAY185]

No pedal height is adjusted by the rod between the pedal and the booster. There is a seperate pushrod between the booster and master that sets the freeplay and basically how far/quickly the piston in the master travels when you put your foot down. If there is too much freeplay you will get a low shitty feeling pedal, akin to poorly bled brakes. It's the last thing to try though. Adjusting rears and thoroughly bleeding has to be ruled out first.

[thecook]

Well, at least the thread title does it justice.

I do feel really stupid. had a bit of a play with the brakes today. I gravity bleed them as explained. While I did get a few bubbles out nothing major. Went all around a couple of times. But still had a soft peddle the car running. long story short I got the and went to get ready for work. Before I left I though I would have a look at ( what I thought was the booster adjuster) it's a adjustable pin at the back of the peddle. I wound it in a few times...... And I got a good peddle.

I haven't had a chance to look at it to much as I was dressed for work, but I did reverse it up the hill and it pulled me up fine. May still be a little spongy at first. But that is the least of the problem.

I wouldn't have thought this adjustment would have made much of a difference. Could someone give me a run down on the mechanics of what may have happened and what I may have done to get it working?

I feel really stupid for asking these questions but there is only one way to learn I guess.

Cheers all for your input

[Bumpy45]

Hey loosecannon, with the motor running will the pedal firm up after a few quick pumps?

[loosecanon]

It wasn't, but now I seem to have a pretty solid peddle all the way through. If the peddle was pumping up that would have told me straight away that there was air in the lines.

[Dannyboy]

Did you adjust up the shoes so there was slight resistance when turning the wheels first before you pushed the pedal, if not the first few times you push the pedal its pushing the pistons out until shoes touch the drum.

[howsie]

Glad you fixed it I wonder if that pedal adjustment would.work for mine its similar but doesn't sink

[loosecanon]

Yea everything was adjusted right. But it wasn't until I adjusted the pin at the back of the peddle ( it runs into the booster) that I got a peddle.
Well worth a shoot it can't hurt to try and adjust it.

Any idea why this fixed problem guys?

[Glenn-80]

Loosecannon, I believe I remember you telling me once brakes are not very important (ye ol' hilux) You must be getting old.

Good to hear you've sorted the issue.

On the note of feeling stupid, I've had more then my fair share.

[loosecanon]

There only important to my engineers. I have my engineer coming down from Townsville next week. My truck will be meeting him up in bundy.
So he made sure I had brakes. and more to the point I think I actually got my handbrake off the transfer to sort of work