Rear brakes locking up on Ninety

[Barreti]

Hi chaps.

This is an old 'problem' but its getting on my nerves a bit that I can't drive the Landy without worrying about the consequences so I thought I'd throw it open for discussion and see what comes out.

I have a 1987 NINETY which was of the panelvan variety (ie, no back windows or seats) until a couple of years ago when I took the roof, side panels and back door off to convert it into a soft top truck cab.
Everything is fantastic except the rear brakes lockup with anything more than the gentlest of brake pedal pressure. I'm guessing this is down to the lack of any weight over the rear axle.

All the braking system is original - disks up front and drums at the back, and although replaced with new a few years ago, the springs and shocks are the original spec too.
Is there anything I can do to adjust the bias?

Thanks for your help
IanB

[GreenLandy]

Sounds a bit like they need re-adjusting at the back. IIRC there are two snail cams that position each brake shoe relative to the drum. These can be adjusted to take into account wear on drums/shoes. I'd take each cam back one notch and then try the brakes. Fitting braided lines to the front might help a bit as well.
If you really think that weight is an issue throw some sand bags in the back. I don't think it is a weight issue the roof and interior of a Landy weigh hardly anything.
HTH
Matt

[R6RY D]

It sounds just as greenlandy says, a bit off brake cleaner and some spanner work is whats called for

[Trooper2]

You might have a bad proportioning/combination valve.

http://auto.howstuffworks.com/master-brake2.htm

[Bluelandy]

Have you checked that the front discs haven't been contaminated with oil/grease? Also if you have any debris in the rear drum this will cause them to lock up. If you've been offroading you should really take all the wheels off and clean/check all brake components.

[bluespanner]

Trooper2 said:

You might have a bad proportioning/combination valve.

http://auto.howstuffworks.com/master-brake2.htm

They dont have them.

My series 2 does this all the time, locking up at the rear that is. Makes for some comical stops at roundabouts and stuff... Its like yonking on the handbrake.

[GreenLandy]

bluespanner said:

[

They dont have them.

Bluespanner you could have at least left Barreti the weekend to figure that one out

[Trooper2]

bluespanner said:

Trooper2 said:

You might have a bad proportioning/combination valve.

http://auto.howstuffworks.com/master-brake2.htm

They dont have them.

My series 2 does this all the time, locking up at the rear that is. Makes for some comical stops at roundabouts and stuff... Its like yonking on the handbrake.

No wonder the rears lock!

[Barreti]

Thanks chaps, looks like the first stop is getting the drums off and cleaning everything up.
I think they've needed this for a while actually as they squeal like a stuck pig, but I didn't know this would contribute to the locking.

Ta

Edited by Barreti on Wednesday 15th August 21:24

[biglepton]

Barreti said:

Thanks chaps, looks like the first stop is getting the drums off and cleaning everything up.
I think they've needed this for a while actually as they squeal like a stuck pig, but I didn't know this would contribute to the locking.

Ta

Edited by Barreti on Wednesday 15th August 21:24

Errr, don't 90's have discs all round?

[Ramthorne]

biglepton said:

Errr, don't 90's have discs all round?

'94 on do, before don't.

[biglepton]

Ramthorne said:

biglepton said:

Errr, don't 90's have discs all round?

'94 on do, before don't.

D'oh! Of course they don't, I forgot my 1989 90 has discs on the back coz it had a later rear axle fitted!

[Matthew-TMM]

I seem to remember reading that for vehicles made after a certain year rears locking before the fronts is an automatic MOT fail.

[Ramthorne]

Matthew-TMM said:

I seem to remember reading that for vehicles made after a certain year rears locking before the fronts is an automatic MOT fail.

I don't see how they could test that without a road test

[Andy Sargeant]

We have just had a similar problem with getting a late import 110" through a SVA test, they test them by driving at about 25mph and apply the foot break, if the rears lock befor the fronts it's a fail.

Can't answer why as we checked everything out, as we said to the SVA men, "it's as most are straight out of the box", even changed brake pads for cheep pattern ones on the front thinking it could make a difference.

We got over this by fitting a break bias block just after the master cylinder which has worked, cost of a bias block was about £40.00, and add a couple of new break pipes and a quick bleed and the jobs done.

But I think in this case it's just a matter of a good strip down and clean, maybe front calipers are seized or posiable blockage in the front flexie hoses.