Found whats causing a rattle but what is it?

[Jim Bowen 1]

its on the passenger side, at the rear of car, underneath, next to the axle mounting, looks like some spring contraption and wobbles about quite a bit, this must be what shudders as i corner

[zak 0]

sounds like the spring on the load biasing valve, shouldnt be loose

[Jim Bowen 1]

well it wobbles about quite a bit, my handbrake is pretty stiff and creaks on hills?

 

can i just take this off and refurb it? looks like it has metal pipes going into it

[dr_mat 0]

Douse the fitting in wd40, get a big pair of grips, grab hold of the arm and waggle it till it's free...

[zak 0]

take a pic of the component in question

[Jim Bowen 1]

not been under car yet, but just looking on ebay and found this, i think this is the same thing i'm on about

 

[dr_mat 0]

i think this is the same thing i'm on about

 

As said above, that's the brake load balance valve. WD40 + waggle it if the arm has siezed.

[Jim Bowen 1]

i want to take it off and refurb it all, if thats possible?

 

will look at it properly but it seemed to be connected up to a few things

[Jim 2]

Yeah - it is connected up to the brake lines! I think you'd probably be better off getting a new one than refurbing it though i've no idea what new ones cost...

[pete_griff 0]

i agree - getting a new one is defnitely the way forward

 

however you will most likely have lots of fun getting the old one off - i have just renewed my brake bias valve and spring - the valve was very much seized on due to the gay, craply designed bolts that hold it on.

they have small allen-key heads and are countersunk into the side of the valve, so you cant get on them with vise-grips. naturally even after lots and lots of plus-gas they still rounded. i cut up through the side of the valve itself with a 4.5" angle grinder to just cut through the bolts enough so that the heads would come off. you would have thought that the valve would then just slide off, but oh no - that was far too simple the ally had corroded all white and galled as ally gets meaning that the valve would not budge at all, even when trying to hammer a thin wedge in between it and the car.

in the end i borrowed a 9" grinder off a friend and cut the whole valve off, leaving just a very thin slice left on the car. i then set about it again with the wedge and hammer and it finally gave way, leaving just the ends of the bolts which i had fun removing with vise-grips - mine was a sod though, so if you aren't particulaly mechanically adept i would get a friend who is to give you a hand just i case you have as much fun as me.

 

also be prepared for the original solid brake lines going into the valve to be swines to undo as well - plus-gas is the order of the day. if you can do it, then renewing the lines with shiny new lines is the way forward, but again you have to have the correct tools etc to do this - so you may want to ask someone if you're not confident and dont have the correct kit...

 

i will post some more pics up in my running gear refurb thread before long and it shows how many pieces i got the old valve off in!

[Bojmobile 0]

What effect does this have if it's failed?

[pete_griff 0]

its called a brake bias valve and does exactly what it says on the tin - it is used to control bias of braking power to the front/rear of the car.

 

if you have a load of kit etc in the boot then it will make the car sit lower on the suspension at the rear. the bias valve is connected to the rear beam via that pivoting arm, but mounted rigidly on the chassis. therefore when the ream beam moves up (i.e when you hit a big bump or have loads of stuff in the boot) the bias valve will allow more braking force to go to the rear than it would if the car was unladen.

its not like it suddenly does all the cars braking at the rear, it just allows more braking force to be used there when necessary.

 

if its broken then your braking forces will be all over the place. also something to note is that if you are lowering a car, you might be as well to take it to an MOT test station afterwards and just get them to check out the braking forces before and after, as lowering a car will probably effect the braking bias. this will hopefully not be too much of a drama though, as if you look at the picture above, the poistion that the spring bolts into the valve is adjustable, allowing you to get the bias somehwere near where it should be.

[Roger Blassberg 0]

Most likely result is too much braking effort on the rear wheels when lightly loaded, which can cause the back end to overtake the front, especially when braking going down a hill. It's there for a very good reason, so it needs to be sorted out. If you have an accident and an eagle-eyed inspector spots that it is defective, he'll smile and walk away from your claim.

 

Best wishes

 

RB

[Jim Bowen 1]

not sure if its related, but i have developed a horrid creaking from the car as i pull away from junctions or drive around town, its exactly as the car moves forward/as you bring clutch up, but seems to be from under car and near to that area

[Roger Blassberg 0]

Could the creaking be caused by a binding rear brake, resulting from a seized caliper? You said at the beginning that the shuddering came when cornering which could be the result of a loose wheel bearing (which would allow the disc to move relative to the brake pads and make a noise), or axle bushes so badly deteriorated that the axle is moving about. Does it steer securely through bends or feel rather vague and erratic? If so, the bushes are probably worn out, although you do get used to it and only really notice the difference once they have been renewed.

 

Best wishes

 

RB

[Bojmobile 0]

Yeah - I had a seized rear caliper and it sounded very much like what you describe.

[Jim Bowen 1]

Could the creaking be caused by a binding rear brake, resulting from a seized caliper? You said at the beginning that the shuddering came when cornering which could be the result of a loose wheel bearing (which would allow the disc to move relative to the brake pads and make a noise), or axle bushes so badly deteriorated that the axle is moving about. Does it steer securely through bends or feel rather vague and erratic? If so, the bushes are probably worn out, although you do get used to it and only really notice the difference once they have been renewed.

 

Best wishes

 

RB

 

the creaking sounds like its coming in a line so to speak underneath the car, hard to describe really, at first i thought it was the plastic tunnel bit that runs between seats as it comes from there, but its not that.

 

i do have something dodgy with a rear brake, the inside/backside of disc is all rusty. Something shudders at the same wheel as i take a corner quite hard, and yes steering/corners are very vague.

 

am suspecting these bushes now, and possibly a wheel bearing.

 

all i can do is put it on my growing list of things to replace. Doing front brake upgrade at the mo, so may as well do rear calipers too, this brake regulator looks crap so probably replace that.

 

am starting to wonder whether its worth buying a 2nd hand axle to refurb with everything over the winter and fit it some time in the new year

[Roger Blassberg 0]

Another cause of the creaking may be that the exhaust system is touching the underside of the car under acceleration. This could be due to weak or broken engine mounts allowing the whole power unit to move and take the exhaust system with it when you let the clutch in. Lift the bonnet, apply the handbrake hard, put in 1st gear or reverse and gradually let in the clutch against a running engine (apply revs as needed to keep it going) and watch to see if the engine rocks fore-and-aft significantly - it's easier if you have an assistant but have him stand to one side, not in front just in case.......!! Look paticularly at the front mount and the one down by the gearbox.

 

Best wishes

 

RB

[Jim Bowen 1]

thats exactly the moment i get the noise, as i lift clutch and you feel it engaging, very strange creaky groin from along the length of car.

 

thanks for all the tips, i really need to get around to sorting all this, no fair when its dark after work :(

[Roger Blassberg 0]

very sorry to hear that you have a strange creaky groin as well :D

 

Best wishes

 

RB

[Walesy 0]

:lol:

[Jim Bowen 1]

oops i meant groan :lol: