Major Brake Issues

[Banshee]

OK so I've just been out to the truck to take a quick look at the job involved, I've had another go with the engine running and there's still no resistance from the pedal at all.

I've just rolled it off the drive and drove it down a very empty street, I gave it a few sharp blasts of the pedal and nothing no resistance at all, when the pedal reaches the floor the brakes do bite and the truck stops dead, I even manage to get it to lock the front N/S wheel :nenau

So the master cylinder is indeed attached with 2 bolts, and has 3 pipes attached to it, 2 on the upper right hand side and one on the lower left which I presume is for the rear brakes

Is this the clevis pin that will need to be removed?

Thanks Guys

 

[rustic]

As mentioned, keep the cap off the top of the old reservoir, drill a small hole in the top to take an air line as mentioned, but you will need to fill the small vent slots, or use a full diameter gasket. To seal it.
Connect it to a tyre, 30 psi and you can pressurise the system.

I have one of those Gunson bleeders, it has a bottle that you fill with brake fluid, and a shrader valve to connect to a spare tyre.
It comes with a range of caps, one fitted the picasso, but not the Mav/Terrano.
A member of this club, sent me a spare cap through the post.:thumb2

The idea is you fill the bottle, fit the cap on the reservoir, connect to the tyre valve, and bleed to your hearts content, but to be honest, I haven't filled the bottle as I couldn't totally guarantee I would get a sealed system, and I didn't want brake fluid at 30 psi spraying around...
But it does work single handed, but keep an eye on the level in the reservoir, and keep a spray of water handy for any spills...
NEVER wipe brake fluid off with a cloth, always wash with water.
Otherwise you will wipe the paint off with it.

Rustic

 

[macabethiel]

Spot ON

As mentioned, keep the cap off the top of the old reservoir, drill a small hole in the top to take an air line as mentioned, but you will need to fill the small vent slots, or use a full diameter gasket. To seal it.
Connect it to a tyre, 30 psi and you can pressurise the system.

I have one of those Gunson bleeders, it has a bottle that you fill with brake fluid, and a shrader valve to connect to a spare tyre.
It comes with a range of caps, one fitted the picasso, but not the Mav/Terrano.
A member of this club, sent me a spare cap through the post.:thumb2

The idea is you fill the bottle, fit the cap on the reservoir, connect to the tyre valve, and bleed to your hearts content, but to be honest, I haven't filled the bottle as I couldn't totally guarantee I would get a sealed system, and I didn't want brake fluid at 30 psi spraying around...
But it does work single handed, but keep an eye on the level in the reservoir, and keep a spray of water handy for any spills...
NEVER wipe brake fluid off with a cloth, always wash with water.
Otherwise you will wipe the paint off with it.

Rustic

Yep this is spot on !

 

[macabethiel]

I've just rolled it off the drive and drove it down a very empty street, I gave it a few sharp blasts of the pedal and nothing no resistance at all, when the pedal reaches the floor the brakes do bite and the truck stops dead, I even manage to get it to lock the front N/S wheel


Thanks Guys

I am still thinking the master cylinder is OK. If you can get the truck to stop and lock a wheel it is creating and holding pressure. The reason the pedal is going down so far is because you are compressing air.
Many years ago I had a similar issue on a Mini me and my mate used a gallon of brake fluid trying to bleed the system and could not get a pedal! The fault eventually turned out to be a rear wheel cylinder letting in air when the pedal pressure was removed but it did not leak fluid ! We clamped all but one of the brake wheel hoses and started bleeding each wheel in turn we had a poor pedal until we got to the faulty wheel cylinder. When we removed the clamp and started bleeding we lost the pedal completely. One rear cylinder replaced brakes then bled OK. Result.

 

[Banshee]

I am still thinking the master cylinder is OK. If you can get the truck to stop and lock a wheel it is creating and holding pressure. The reason the pedal is going down so far is because you are compressing air.
Many years ago I had a similar issue on a Mini me and my mate used a gallon of brake fluid trying to bleed the system and could not get a pedal! The fault eventually turned out to be a rear wheel cylinder letting in air when the pedal pressure was removed but it did not leak fluid ! We clamped all but one of the brake wheel hoses and started bleeding each wheel in turn we had a poor pedal until we got to the faulty wheel cylinder. When we removed the clamp and started bleeding we lost the pedal completely. One rear cylinder replaced brakes then bled OK. Result.

Makes sense mate :thumb2

I've just replaced the rear O/S slave cylinder and bled the system when I did that one and it took all of 10 mins and the brakes were sharp as you like again

I think before I start replacing the master cylinder needlessly I'll try another bleed tonight, my mates a truck mechanic and he's given me another 5 litres of fluid for gratis :clap

 

[micktheshed]

Probably yours is OK but have you also checked for a cracked bulkhead allowing movement of the master cylinder, worth doing just to be sure. I had this prob. on a Montego which not only was susceptible to cracks but also flexed considerably resulting in crap bakes no matter what!

 

[Kishada]

I am still thinking the master cylinder is OK. If you can get the truck to stop and lock a wheel it is creating and holding pressure. The reason the pedal is going down so far is because you are compressing air.
Many years ago I had a similar issue on a Mini me and my mate used a gallon of brake fluid trying to bleed the system and could not get a pedal! The fault eventually turned out to be a rear wheel cylinder letting in air when the pedal pressure was removed but it did not leak fluid ! We clamped all but one of the brake wheel hoses and started bleeding each wheel in turn we had a poor pedal until we got to the faulty wheel cylinder. When we removed the clamp and started bleeding we lost the pedal completely. One rear cylinder replaced brakes then bled OK. Result.

As per this post it is a very very good idea to clamp off a flexi hose at a time or continue to clamp them off until the pedal potentially improves showing the line at fault.

 

[Banshee]

Finally Fixed!!!!!

What a piss take this one turned out to be!!!

On Rustic's advice I decided to buy an eezibleed kit, knowing that they didn't come with a cap for the Master Cylinder Reservoir I darted to the scrap yard near me after work with my Nan and ran in 3 mins before they were to shut and grabbed the cap off the 2.4 petrol they had in there :thumb2

Got it all home and decided to get modding :thumb2

After a nice cleanup

10mm hole and the pipe went in beautifully

I started the bleed process and still had the issue :doh

Luckily at that point my mate came round who is a truck mechanic and offered to help me out, with him in the car and me on the bleed nipples we figured out that the issue was the front left caliper...................... the one I'd just replaced!!!!!!!!! :doh

Removed it and replaced it with my old one that I removed as I suspected it had a seized piston but it appears that it is actually OK. Just has damaged dust seals.

Wahey :clap Working brakes again BUT car still pulls to the right under braking

I don't think it helps that my torsion bar is slightly lower on the right hand side of the car (will shortly be re-indexed due to LWB springs being fitted) also my drivers side droplink has snapped which are soon to be replaced by a set of the rose joint ones that exosteve as been knocking up :thumb2

 

[Kishada]

What a piss take this one turned out to be!!!]

I started the bleed process and still had the issue :doh

Luckily at that point my mate came round who is a truck mechanic and offered to help me out, with him in the car and me on the bleed nipples we figured out that the issue was the front left caliper...................... the one I'd just replaced!!!!!!!!! :doh

Removed it and replaced it with my old one that I removed as I suspected it had a seized piston but it appears that it is actually OK. Just has damaged dust seals.

Wahey :clap Working brakes again BUT car still pulls to the right under braking

I don't think it helps that my torsion bar is slightly lower on the right hand side of the car (will shortly be re-indexed due to LWB springs being fitted) also my drivers side droplink has snapped which are soon to be replaced by a set of the rose joint ones that exosteve as been knocking up :thumb2

As per macabethiels post you would have picked this up by clamping flexi hoses.
Glad you found the problem

 

[Banshee]

As per macabethiels post you would have picked this up by clamping flexi hoses.
Glad you found the problem

That's kind of how we did it, thanks for all the input guys :thumb2

 

[solarman216]

something is still not quite right, if it was your front calliper, why was the pedal going to the floor, it should have stopped short of the floor on the rear brakes, so you still have an issue as far as I can see, either your rear brakes are US or your master is passing between the front and rear, Rick

 

[rustic]

:bow

something is still not quite right, if it was your front calliper, why was the pedal going to the floor, it should have stopped short of the floor on the rear brakes, so you still have an issue as far as I can see, either your rear brakes are US or your master is passing between the front and rear, Rick

Rick, I was thinking about this too the other day.
Now we know the rear auto adjusters don't work too well, so maybe they require a lot of fluid to push them against the drums, hence the movement.
If these were manually adjusted, then that might reduce the stroke in the master cylinder.

The handbrake is not that good on these trucks unless these adjusters are on the limit.
Just a reminder, on how to adjust the handbrake, slacken off the adjuster under the handbrake lever, then remove drum(s), and adjust auto adjusters manally, using a screwdriver to turn the little cog with the spring clip on. One click at a time...

Adjust until you can just get the drum back on.
Do both sides, then take up the slack on the handbrake.
Check for any binding, and consequent overheating, and slacken off if required.

Sorted.

This technique, really does improve the handbrake efficiency.:thumb2

 

[solarman216]

Thanks Rustic but you are teaching grandma to suck eggs, tell tale button on rear back plate tells all, Rick

 

[Banshee]

Not really sure whats going on guys :nenau

All I know is that my brakes are working well now

I might jack the car up on the rear and get someone to sit inside and test the brakes while I check the rear wheels for movement

 

[solarman216]

That reminded me of when I first started work in a commercial workshop, plating and testing for trucks had just been introduced, my governor reckoned that if you jack up a ten tonner and apply the brakes then if he could not turn the rear wheels with a wheel brace and a ten foot bar then the brakes are good, I laughed and told him straight what a fool he was, so anyway took truck to new testing station and it failed miserably on the rear brakes, my method was to jack up rear run engine in first gear, full revs and apply brakes, a bit evil on the chassis but as a guide it should stall the engine, (stopped test before it stalled though) I hasten to add this is not a test any where near what the brakes have to do in real life but it did give a rough guide on a truck that we were trying to asses prior to testing, bearing in mind that we only ever saw a truck when it was empty, and a road test empty was a wast of time, Rick