Rear brake lock up

[Mountain Goat]

Guys (Girls?)

I've been living with this for a while but have got access to a decent ramp for a week so I want to cure it.

Since fitting new rear shoes approximately 5000 miles ago the rear brake or brakes are very sharp. I would say specifically the rear nearside but its difficult to say. At it's worst on a wet road or gravel it will lock up bringing the ABS into play considerably earlier than I feel it needs to. I hope that makes sense.

After servicing the car today I took off both rear drums and blew out all the brake dust and had a good look. All shoes appear to be wearing evenly and there are no other obvious faults. This issue is really noticeable in the morning after the car has stood overnight. The first dab of the pedal tends to want to put you through the windscreen. Thanks in anticipation of your replies.

Goat

You can look at it as long as you like. It won't dig itself.

 

[Lazy-Ferret]

Purely a guess, but does it have one of those load sensing valves behind the rear axle, I wonder if it is reporting the car has a boot full of stuff when it does not.

As I say, purely a guess, as I have not had to even look at my one yet.

 

[rustic]

Once in 17 years I managed to skid one of the rear wheels whilst braking.

Normally the front pick up first.:nenau

Brake load valve would be my first guess, unless you have fitted the wrong diameter rear wheel cylinder.

There are two sizes, but most factors only supply one size.
Ie one size fits all. Well most of the time.:doh

I over adjust my handbrake so it only takes 3 clicks to make a big difference, and will hold on a small incline, and I can't get my rears to lock.

Hope this helps.

Rustic

 

[solarman216]

as Rustic says, load sensing valve, the difference in cylinder size is only 1 mm small for SWB larger for LWB so would not be enough to cause lock up and in my experience the suppliers supply the smaller one anyway, with the HB off and wheels chocked can you push the tell tale buttons in on the bottom of the backplate? and if so by how much? Rick

 

[briggie]

i realise i know nuffin , but i seem to remember a mechanic filing the edges of the brake pads when fitting them in the rear shoes , i dunno if this is relevant tho :nenau

 

[Banshee]

This reminds me, I need to replace my load sensing valve as when under no load at low revs it rattles like hell however when I have the boot full and or passengers in the back It's fine

 

[geoffdown]

Guys (Girls?)

I've been living with this for a while but have got access to a decent ramp for a week so I want to cure it.

Since fitting new rear shoes approximately 5000 miles ago the rear brake or brakes are very sharp. I would say specifically the rear nearside but its difficult to say. At it's worst on a wet road or gravel it will lock up bringing the ABS into play considerably earlier than I feel it needs to. I hope that makes sense.

After servicing the car today I took off both rear drums and blew out all the brake dust and had a good look. All shoes appear to be wearing evenly and there are no other obvious faults. This issue is really noticeable in the morning after the car has stood overnight. The first dab of the pedal tends to want to put you through the windscreen. Thanks in anticipation of your replies.

Goat

You can look at it as long as you like. It won't dig itself.

mine is the same as urs but with mine it looks like the prevous owner took sensing valve off as there is no valve above osr axle so this is what could be wrong with mine:nenau

 

[makeitfit]

mine is the same as urs but with mine it looks like the prevous owner took sensing valve off as there is no valve above osr axle so this is what could be wrong with mine:nenau

ooph, if you've no load sensor valve you've got way too much rear bias No wonder it's locking up but at least your front pads will last longer :lol

 

[Mountain Goat]

Thanks, load sensing valve then. Will have a look.

 

[geoffdown]

ooph, if you've no load sensor valve you've got way too much rear bias No wonder it's locking up but at least your front pads will last longer :lol

No that's the strange thing it's the front that locks up and abs cuts in on front wheels sliders are all nice and free as I checked them last weekend:nenau

 

[melissachels]

Thanks, load sensing valve then. Will have a look.

i was in nissan today checking the price for my clutch pedal spring & bushes, just out of interest i got them to price up the brake load sensor/ load sensing valve.....i hope your sitting down ..........£341.21!!!

 

[dollywobbler]

No that's the strange thing it's the front that locks up and abs cuts in on front wheels sliders are all nice and free as I checked them last weekend:nenau

In that case I wonder if the rears are doing anything at all. Jack up the rear (both wheels, so chock the fronts) get an assistant or jam down the brake pedal and see if you can rotate the rear wheels. I got a shock when I did this on mine once as the rears span quite happy! (wheel cylinder leak seemed to have allowed the level to drop sufficiently to allow air into the rear brake circuit).

 

[makeitfit]

Bloody ABS you never told me that :lol
I did a thread on a manual bias valve instead of a load sensing valve
I too thought Nissan's price a tad on the "fookin' hell HOW MUCH" side
Although it's a trol the same work applies :thumbs
http://www.nissan4x4ownersclub.com/forum/showthread.php?t=16574&highlight=bias