Major Brake Issues

[Banshee]

Guys help me

I was sat at McDonalds drive thru the other night with my foot on the brake and as I reached into my back pocket for my wallet the brake pedal just went to the floor.

I got out the car and looked underneath and it appeared that my passengers side brake pipe had developed a split and I'd started to lose fluid on the floor :doh

I've now got a replacement pipe from a scrap Maverick and fitted it, I've also fitted a new passengers side caliper as I believed that mine had a seized piston which was causing my car to pull under braking.

Everything went back together perfectly however I've been trying to bleed the brakes and I have been unsuccessful

I've had an assistant pump the brakes until it goes hardish, then push down and hold, I crack the bleed nipple, pure fluid comes out, I re-tighten the bleed nipple and then the assistant looses the pedal out, I have done this at least 5 times per caliper and have used at least 1 litre of fluid doing this.

Once bled and all the nipples re-tightened the pedal goes straight to the floor :nenau

You can pump it which makes it firmish but then again the pedal just returns to the floor after a few seconds

I'm really at a loss here :nenau

Any help will be greatly appreciated guys :thumbs

 

[rustic]

Thank goodness you were stationary at the time:augie:augie

First thought is the seals in the master cylinder have inverted, or become damaged.

I had read on here, that when bleeding the brakes, never allow the pedal to go to the floor, as it can damage the seals in the master cylinder.
So since yours has gone to the floor, then maybe this is what has happened.

It would explain it.

Unless you have another leak, I can't think what else it is...:nenau

So is the fluid in the reservoir now at a constant level ie showing no loss?
EDIT...
Found this post..
http://www.nissan4x4ownersclub.com/forum/showthread.php?t=2294&highlight=bleeding+brakes


Rustic

 

[makeitfit]

I can't see full pedal travel being the cause. It's possible you've got air in the system still though. Assuming the master cylinder hasn't popped it's clogs I'd do full bleed on it. So try that 1st inc brake compensator and then think about m/c :thumbs

 

[solarman216]

I would say your master cyl has failed, defo not safe to drive, I have a used cyl if you need one, as the cyl is a two part one even with a busted front hose it should not hit the floor as the rear brake bit should still be functioning, Rick

 

[rustic]

I would say your master cyl has failed, defo not safe to drive, I have a used cyl if you need one, as the cyl is a two part one even with a busted front hose it should not hit the floor as the rear brake bit should still be functioning, Rick

Unless the intermediate seal had already gone, how would you know?

 

[solarman216]

Unless the intermediate seal had already gone, how would you know?

you would not, but for it to hit the floor points to master failed, Rick

 

[macabethiel]

Brake problem

I have never had a brake master cylinder fail in 47 years of running mostly cars over 5 years old and in some cases 20 years old.
I know they can fail but if a brake pipe has failed then its going to be linked to bleeding the brakes.

Not sure how much you value your life never mind anyone else's but I have never fitted second hand brake pipes or hoses even when skint. After market hoses are reasonably priced I have found.

That aside I use any Easy Bleed so you are pushing clean fluid down from above. I made my own in the past by obtaining a spare reservoir cap, drilling a hole in it and fitting a tubeless tyre valve. Overfill the reservoir then fit modified cap and with a pump or hose from a tyre pressurise the system.
On some more modern cars they have a separate vents on the reservoir so this will not work. I have found that a series of quick and slow depressions of the pedal can help always starting from the most distant cylinder or calliper on the system.

 

[Kishada]

Possibly air trapped in the ABS pump.
Hard to do with a crap pedal, but if possible, get some speed up, slam on the brakes and get the pump to fire if you can lock up some wheels.
Easy and almost a necessity to bleed the brakes by firing the pump on VAG cars with diagnostic eqpt as soon as you touch the hydraulic system, otherwise the pedal travel is normally significantly longer after work has been done.

 

[solarman216]

it is a 96 not sure ABS was fitted then, if it is ABS then I stand down as never had dealings, Rick

 

[makeitfit]

I dont think there's abs on 96 truck :nenau

 

[Banshee]

Thank goodness you were stationary at the time:augie:augie

First thought is the seals in the master cylinder have inverted, or become damaged.

I had read on here, that when bleeding the brakes, never allow the pedal to go to the floor, as it can damage the seals in the master cylinder.
So since yours has gone to the floor, then maybe this is what has happened.

It would explain it.

Unless you have another leak, I can't think what else it is...:nenau

So is the fluid in the reservoir now at a constant level ie showing no loss?
EDIT...
Found this post..
http://www.nissan4x4ownersclub.com/forum/showthread.php?t=2294&highlight=bleeding+brakes


Rustic

No other leak anywhere as far as I can make out, the fluid in the resevior tank stays at the same level now so not loosing any

I can't see full pedal travel being the cause. It's possible you've got air in the system still though. Assuming the master cylinder hasn't popped it's clogs I'd do full bleed on it. So try that 1st inc brake compensator and then think about m/c :thumbs

I'm pretty sure there's no more air I bled it for ages!!!!!

Is the master cylinder a big job?

 

[Banshee]

No ABS on my '96 guys

I like the idea of the easy bleed kit, Is there one on the market that you can buy or do you have to make your own?

 

[bry]

Yeah plenty of self bleed kits out there.

 

[solarman216]

No ABS on my '96 guys

I like the idea of the easy bleed kit, Is there one on the market that you can buy or do you have to make your own?

as I have stated before have never bled any of my terrano's in the conventional manner, mainly because most bleed nipples shear, so I do not risk it, it is really very simple, for the front just remove the calliper, and press the pedal a few times to extend the pistons then with a G cramp push the pistons back home, all air will end up in master cyl, same goes for the rear allow the pistons to go as far as the dust boots allow then push them back as far as they will go all air will go up hill no problem, Rick

 

[Banshee]

as I have stated before have never bled any of my terrano's in the conventional manner, mainly because most bleed nipples shear, so I do not risk it, it is really very simple, for the front just remove the calliper, and press the pedal a few times to extend the pistons then with a G cramp push the pistons back home, all air will end up in master cyl, same goes for the rear allow the pistons to go as far as the dust boots allow then push them back as far as they will go all air will go up hill no problem, Rick

I'll have to try that technique I think but I'm pretty sure now from what has been said that the master cylinder has died a death

Is it a big job to replace it?

 

[solarman216]

I'll have to try that technique I think but I'm pretty sure now from what has been said that the master cylinder has died a death

Is it a big job to replace it?

no clevis pin inside motor, two bolts master to body and the brake pipes, plus vac pipe, about an hours work if that, probably will not need bleeding if you fill reservoir, and allow fluid to flow while connecting brake pipes, Rick

 

[Banshee]

no clevis pin inside motor, two bolts master to body and the brake pipes, plus vac pipe, about an hours work if that, probably will not need bleeding if you fill reservoir, and allow fluid to flow while connecting brake pipes, Rick

The clevis pin will be attached to the brake pedal right?

The two bolts, will they need undoing from the inside of the truck or in the engine bay?

 

[solarman216]

The clevis pin will be attached to the brake pedal right?

The two bolts, will they need undoing from the inside of the truck or in the engine bay?

clevis pin inside all the rest engine bay real easy, Rick

 

[Banshee]

clevis pin inside all the rest engine bay real easy, Rick

Thats what I like to hear

Rick, I've been looking at some on eBay and some are just the master cylinder and some have the big cylindrical servo on the back as well, would I need to replace the two or just the cylinder?

 

[Banshee]

Also, this one appears to have 3 threads and would look to me like it would have nuts inside the truck? :nenau