Outer Limits 4x4 Board

More brake probs for me.
I need your advice on this one guys/girls.

Ive just put the vented rotors and bigger calipers on my LN65, I was going to fit the 80series master cyl and booster but I dont have a bench vice(to bench bleed the thing) so I thought, I could just get the Lux back on the road which means I can drive around, and when I get some more money, I can then worry about fitting the master.

Anyway, I bled the brake system yesterday about 8 times, and 3 times so far today. There is still air in there somewhere.

The method I used to bleed is the same method I used a couple of months ago, and it worked then.

I have a glass jar about 1/3 full of clean brake fluid, and a piece of clear hose from the bleed nipple to the fluid.
I put the clear hose over the nipple then loosen it, pumping the brake pedal down about halfway until the air bubbles stop and only fluid comes through, then I hold the brake pedal down with a length of 4x2, tighten the nipple then remove the wood, top up the fluid bowl and move on to the next brake.
Im starting at the passenger rear, then drivers rear, passenger front, drivers front, then the LSP valve thing last.

Ive done this quite a few times now and the brakes are still not working at all.

When I was changing calipers over, the fluid bowl did run dry. I have a feeling thats part of the problem.
Like I said, I dont have any way of bench bleeding the new master so if I was to fit the new master and booster, it would be a bolt in job then bleed it.

Is it possible to get all the air out of the master and then the rest of the braking system after it has been fittied to the engine bay??

Its starting to give me the shits.

you can do it all in the car no probs
you just need a mate to pump the pedal for you
while you get down and tweak the nipples

You can bleed the master on the car by running two pipes from the master back into the reserve. fill it with some fluid and pump until there are no more bubbles coming up the pipes.

Also the order of bleeding the calipers and lspv is done in order of the longest fluid line to the shortest, from the master cylinder. If the lsvp is on the chassis above the axle then it will have to be done before the front calipers.

Everywhere Ive read says to bleed the LSPV last.

I took out the lux master cyl and booster this arvo, need to trim out the hole in the firewall, as the pushrod on the 80series booster sits a bit higher than the lux one.

I also snapped one of the hard brake lines trying to loosen it.

More god damn dramas.

Ill keep plodding along with it, I dont have much choice now.

Eventually, Ill have brakes again.

Are the callipers fitted on the correct sides? Just make sure the bleed nipples are at the top of the callipers when bolted onto the car. Otherwise I can't see any reason as to why you can't get a decent feeling pedal.

a little trick i use to bleed up a new master is to take out the fron disc pads place in a small spacer to stop the piston hitting the disc(falling out) then pump the pedal so the pistons are almost fully out i do the same in the rear...

then install the new master wedge the pedal down 90% before you hook up the brake lines ..half fill with fluid then slowly 1 wheel at a time refit the pads pushing the pistons back in this is a sneeky way of back bleeding

you should find the the system will be just about air free..
i got this tip from a brake place as they do it to save time and air problems

Vacuum Bleeder

tehekho wrote:Vacuum Bleeder

Suction and nipples is always an attractive proposition

all we do at work to bleed new master is block all the holes where the brake lines screw in,fill half full and pump it with your finger

Thanks everyone for your help.

An update....

I fitted the 80s booster and master cylinder, got it all plumbed up, bled the system good.
Now I have brakes.

But when I push brake pedal down, the pedal feels solid, the brakes grab and stop the car but it rocks forward and back a couple of times.

I know somethings not quite right, I know its not supposed to do that.
Does anyone have any ideas??

Is there still air in the system??
The front brake rotors and pads more than likely havent been used for a while, so could t just need me to stomp the brakes and lock up the fronts to bed them in a bit??

it shouldn't be air in the lines if you have a consistant solid pedel. does youre pedel need pumping to get it solid again?? if not, well it won't be air in the lines.

p.s. a trick i used to use was we made the resivoir sealed and place an air line to it, and opened all the break nipples up and just pushed it through making sure we didn't run out of fluid,

DUDELUX wrote:... pumping the brake pedal down about halfway until the air bubbles stop and only fluid comes through...

Mate, I always push the pedal to the floor when bleeding the brakes. You may have had a big bubble trapped in the master cylinder.

BadMav wrote:

DUDELUX wrote:... pumping the brake pedal down about halfway until the air bubbles stop and only fluid comes through...

Mate, I always push the pedal to the floor when bleeding the brakes. You may have had a big bubble trapped in the master cylinder.

This is fine with a new master cyl but when bleeding a used master (or one that has been on the car a while) it is not advisable to go down to the floor as you are pushing the piston past its "usual" stroke and can potentially pick up crud which may damage the bore/piston or seal and cause the master to bypass. Halfway/three quarters down is more than enough. It might just take a few more strokes to purge the air.

Dudelux, what do you mean "it rocks forward and back a couple of times"? The pedal? Sounds like a sticky caliper piston. Where they second hand or reconned?

The whole car rocks forward then back, a couple of times.
The brakes grab and stop the car from moving anywhere, but this rocking is wierd.

I bled the system today, again, then I fitted the drivers front wheel and tested the brakes wile it was still on jackstands, the brakes worked, so I put all 4 wheels back on.
As I was reversing out of the shed, I put the brakes on to test them, and it rocked forward and backwards.

The master cyl and booster were just good ones from the wreckers, same with the calipers.

The fronts seem to work good, just this rocking is wierd.

Should I bleed the system another couple of times??
Should I just drive down the street and jump on the brakes to try and bed in the fronts?? Im not sure how long the brakes have been sitting on the shelf at the wreckers.

Was the 80 series master cylinder of a disc front and rear 80 series? There might be too much pressure going to the back brakes causing the rocking.

Can you reduce pressure to the rear by adjusting the lspv?

No, the master and booster are from an early 80, disc front and drum rear.

Hey guys don't mean to crash the thread, i just have a quick one since we are on the subject.
im in the middle of doing my brakes aswell, have gone to bleed and found the bleed nipples were blocked, i have unblocked but the rear passenger bleed nipple is constant open (always pushing out fluid) i have tried two other nipples and they did the same, im thinking wheel cyl, i havent had a chance to pull appart, just want to know what i may be getting into,

cheers
loose,,

sorry again for crash'n the thread

DUDELUX wrote:The whole car rocks forward then back, a couple of times.
The brakes grab and stop the car from moving anywhere, but this rocking is wierd.

I bled the system today, again, then I fitted the drivers front wheel and tested the brakes wile it was still on jackstands, the brakes worked, so I put all 4 wheels back on.
As I was reversing out of the shed, I put the brakes on to test them, and it rocked forward and backwards.

The master cyl and booster were just good ones from the wreckers, same with the calipers.

The fronts seem to work good, just this rocking is wierd.

Should I bleed the system another couple of times??
Should I just drive down the street and jump on the brakes to try and bed in the fronts?? Im not sure how long the brakes have been sitting on the shelf at the wreckers.

Are the rears working too well? It may just be that they are working better than before. Does the car rock when going forward, or just backwards?

loosecanon wrote:Hey guys don't mean to crash the thread, i just have a quick one since we are on the subject.
im in the middle of doing my brakes aswell, have gone to bleed and found the bleed nipples were blocked, i have unblocked but the rear passenger bleed nipple is constant open (always pushing out fluid) i have tried two other nipples and they did the same, im thinking wheel cyl, i havent had a chance to pull appart, just want to know what i may be getting into,

cheers
loose,,

sorry again for crash'n the thread

Pull the nipple completely out and clean the seating area inside the wheel cylinder. If that doesn't fix it just buy a new wheel cylinder, they're cheap.

The rear brakes are in need of attention, and the handbrake hasnt worked for a while.
Its rocks no matter which direction Im travelling in.
I never had this happen before, so if I can get the system working properly and have them stop me, then I can get around until I can get into the drums.

Shock stuffed and brakes actually stopping and holding the car now?

The shocks are from factory so yeah probably not in the best condition being 24yrs old.

Its wierd.
Should I just go up the street and jump on the brakes to see if I can bed them in a bit??

I just rang a local brake specialist, and told him whats happening, he asked a couple of questions and after a bit of a chat, he said maybe I should go for a drive around the block a couple of times and try to get the discs bedded in a bit.
The discs have been sitting at the wreckers, unsure how long, but there is a little bit of surface rust on them, and that maybe whats causing it to happen.
He said not to jump on the brakes, but to use them to try and rub the surface of the disc back.
Does that make sense??

.
Jumping on the brakes will lock the disc up.... if you have surface rust om then you will need to use them correctly or even drive while pressing the brakes for short periods becarefull not to over heat them. You should have cleaned the rust on them first.
Also New pads on old discs that havent been machined will never work real well for some time. My suggestion is to have the discs machined.

Hence why brakes should be left to the professionals.... apart from steering the most inportant part of the car.

The pads arent new, they have heaps of life still on them.
The discs were cleaned by me, but I couldnt get them perfect.

I wasnt going to gun it up the street, and then lock up the fronts, not at all.
I will just cruise around slowly, maybe 3rd gear, and push as I would normally to slow down, until they come good.
Ill see what happens.

There is a reason why you have to be a qualified electrician to work on 240 volts and the same should apply for brakes on a car. Will you remember how much money you saved by doing the job yourself when your handing over your insurance details to the other driver?
I'm not being critical directly to you dudelux but just generaly speaking.

im being critical... retard

First up Twon, eat a dick!!!

The gun, at the moment Im not working so money is non-existant, so everything that happens, has to be done as cheaply as possible, Im not saying Im an expert, you probably already knew that from reading this thread.
Im not one to try and halfass things either, if I am about to tackle a job Ive never done before, then of course Im not going to be confident. Which is why Im on here asking what alot may see a dumb questions, Id rather look like a retard and ask the dumb questions so I can be at least a little bit prepared for the job Im about to tackle.
Im sure at some stage, we have all had to do a job weve never done before.

I didnt post these questions to be called a retard, I asked for help on how to fix a problem that has me baffled.

pull the discs out and clean them up with a wire brush that goes onto the drill or grinder.
pull your pads out and rub in circles while applying pressure over clean cement.
make sure you do it in circles though

the gun wrote:There is a reason why you have to be a qualified electrician to work on 240 volts and the same should apply for brakes on a car. Will you remember how much money you saved by doing the job yourself when your handing over your insurance details to the other driver?
I'm not being critical directly to you dudelux but just generaly speaking.

Work must be a bit slow, aye?

georgey wrote:pull the discs out and clean them up with a wire brush that goes onto the drill or grinder.
pull your pads out and rub in circles while applying pressure over clean cement.
make sure you do it in circles though

Just have the disc's machines and fit new pads and be done with it, cleaning the rust off the discs isnt going to fix the imperfections within the disc