LN130's and brakes, or lack of...

[AndyLala]

Gentlefolk,

as you may or may not know... brakes have been a minor obsession of mine for some considerable time.

Perhaps because I understand the braking system well enough, perhaps because I haven't got a clue.

Brake pedal is applied, piston moves in master cylinder, fluid is forced around the system, brake pads are applied to the discs or drums.

Simple enough...

We have vaccum assist to apply more pressure than some of us could manage with one foot... and bob is your sisters husband.

So, as we add bits to our toys, they get heavier... as we increase the size of our tyres... etc. etc.... we need stronger brakes... and so it begins.

One of the popular mods is to fit an 80 series master cyclinder... 1" bore (apparently)... popular in the states.... note, the 80 series master cyclinder exits out on the left hand side looking forward. Great in a left hand drive vehicle, as your heat shield would be on the right... not so good on a right hand drive vehicle, as it interferes with the heat shield... (on a 2.4) [ anyone want a brand new 80 series master cylinder...? ]

So, what can we do with our right hookers... well, the 3rd gen master cylinder is handed too... pipes exit out on the right, for a right hand drive... and the bore is half way between a 2nd gen MC and an 80 series... Its also a perfect fit, everything lines up.

Braided brake hoses, take the slack out. Job should be a good 'un... should be...

so why won't the system pressurize... first press goes all the way to the floor... second press is rock hard... truck nearly stands up on its front wheels.

I have tried everything, short of changing the hard lines... everything is new... a spanner in the works was a cracked caliper, weeping ever so slightly... yet another one... (Barry at Roughtrax is an absolute star, customer service rocks with those guys)

Can anyone suggest anything at all... I am about to set fire to the truck...

And if anyone comes along with a sensible offer, its thiers... I'll even put a bottle of bubbly in the back.

[MattF]

If it's working fine on the second press, then you have air in the system somewhere.

Edit: Not meaning to take the p1ss or anything, but you did actually bleed the system after fitting the master cylinder?

[AndyLala]

Its only been bled on about three separate ocassions over the last month and is getting progressively worse.

Anyone got any matches?

On a serious note, anyone got a fool proof method of bleeding the brakes, that doesn't require copious amounts of swinging wildly with a pick axe handle... (clears most of my frustration...)

[GRASSMAN]

Try bleeding the n/s/r first, then o/s/r, n/s/f and finish with o/s/f. Open bleed valve, press the pedal slowly, close the bleed valve at end of each stroke, lift pedal and repeat untill no bubbles appear. Or try to get hold of a pressure bleeder kit, I've used these with great success on old minis (worst one took 3 days) Lastly have a helper press the pedal hard and check underneath for leaks at all the joints and unions, also check for any dampish pipe work down there. Hope this helps!!

[AndyLala]

arhhh....

absolutely right... but what about the load sensing valve... where does this fit in with the program.....

surely start with the shortest pipe first, then work through to the longest...

[stormforce]

its like grassman says you always start from the furthest point and work towards the nearest point to the reservoir
I've got one of those Gunson eezibleed kits which i have yet to try out.
You connect it to the spare tyre and then to the reservoir and then and open each bleed nipple in turn and it forces the old fluid out while continuing to keep the reservoir full so there's no need to keep pupmping the brakes.The fluid is only pushed out one way so you should get any air out from the system easily and quickly

[AndyLala]

Tried one of those Gunson things a while back, but couldn't get it to fit the MC properly...

Does anyone bleed the LPSV? and is the general consensus to go longest pipe first...? I thought it was shortest to longest...?

Hey, I am at the point where I will now try anything... thanks for the suggestions guys...

[darkdezigns]

defiately longest to shortest

[nero279]

yep longest to shortest, n/s rear, o/s rear, n/s front, o/s front.

I did LSPV after the two rears. I also found that adjusting the handbrake cable at the bridge bit in front of the fuel tank also seemed to affect the footbrake.

[BUSHWHACKER]

Sounds like the servo is leaking vacuum. Are the hoses leading to it sound/secure?
Or the seals are worn in the M/S.

[boris]

tried bleeding brakes before with one of them ezi bleed things. two days later i took it to my local garage who charged me a tenner... problem solved.

[NiftyNev]

Bleed the master cylinder then the brake lines.

Nev

[AndyLala]

I hope the master cyclinder isn't leaking... its brand spanking new...

I'll try and get it sorted again on Monday...

Thanks everyone for all your help and advise... much appreciated.