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Getting really cheesed off now

Posted: Sat Nov 03, 2007 5:34 pm
by poppet
'Blanche' is getting to be a really big pain as she is turning me into a Morris Minor enthusiasts widow(ie I never get to see the man)
Here is the latest problem:
She came to us with disc brakes and telescopic shock absorbers
This weekend she has had on her passenger front
new caliper
new brake pads
new wheel bearing
new track rod end
top and bottom trunnions checked/cleaned and put back with new bushes
After all that she still makes a noise like metal on metal when turning a right corner. The noise is lessoned greatly if the corner is turned with brakes applied. She does not do it when driving normally - only when turning corners and she does not do it on the left turn
Helpful ideas please
Thanks
Liz

Posted: Sat Nov 03, 2007 5:45 pm
by MoggyTech
Common with some types of disc brake mods. The problem is likely to be the outer edge of the disc rotor rubbing on the caliper mounting plate, where the rotor passes close to the mounting plate openings on either end.

2 possible fixes.

1: Check for and remove any rust build up on the end face and edge of the disc rotor.

2: Remove caliper mounting plate and check for 'witness' marks where the rotor has been rubbing. Using a file or dremel type rotary tool, remove 0.5mm of metal from the caliper mounting bracket where the rotor has been rubbing.

Also worth checking wheel bearing adjustment (if taper bearings), or hub nut tightness if standard bearings.

Above all applies to Ford Calipers, with Marina Hubs and Rotors.

Posted: Sat Nov 03, 2007 6:04 pm
by Kevin
Did you not check before you replaced things to see if you could replicate the noise with the car stationary to make sure you had got the faulty side as its the offside that takes the load when turning right, also pads should always be changed in pairs and you have checked that the tie bar rubbers are all OK.

Posted: Sat Nov 03, 2007 6:38 pm
by MoggyTech
[quote="Kevin"] its the offside that takes the load when turning right,quote]

Surely the nearside takes most of the load when turning right? G Forces will cause the car to lean harder on the left suspension when turning right due to body roll (weight shift.)

Posted: Sun Nov 04, 2007 7:39 pm
by bmcecosse
How much clearance is there between the disc and the caliper jaws ? You need to make sure the caliper is absolutely central on the disc - equal gap both sides.

Posted: Mon Nov 05, 2007 1:53 pm
by dunketh
Don't be cheesed off with the poor thing.

Its often the case that you're playing 'catch up', bits failing quicker than you can fix them! The god news is - you win in the end*!


(*there are only so many parts you can replace. lol)

Posted: Mon Nov 05, 2007 2:02 pm
by jonathon
Sounds like loose hub bearings, allowing the play needed to contact the caliper bracket. Holding on the in a corner will both lessen the amount of allowed travel and centralise the disc more.
If the disc kit has an aluminium hub, then check the bearing cups, its a common fault that they often they work loose so the bearing assemblies are floating around. If this is the case then you will need to replace them(the hubs) as the location for the bearing will now be of no use at all. Do not be tempted (as is suggested by the supplier) to loctite them in place.

Posted: Mon Nov 05, 2007 2:11 pm
by dunketh
Do not be tempted (as is suggested by the supplier) to loctite them in place.
fpmsl..

Seriously? Even I wouldn't glue wheel bearings into a hub - and I'd do most things. :lol:

Posted: Tue Nov 06, 2007 12:19 pm
by Kevin
Surely the nearside takes most of the load when turning right? G Forces will cause the car to lean harder on the left suspension when turning right due to body roll (weight shift.)
MoggyTech sorry to disagree but when I turn right the car the car dips so to speak on the r/hand (offside) as it leans into the direction being turned into and the force on the nearside is decreased due to body roll, please explain if I have got the wrong end of the stick.

Posted: Tue Nov 06, 2007 3:38 pm
by MoggyTech
Kevin,

I cannot for the life of me, see how a car can put the shifted weight onto the right hand wheel when turning right. If you look at any photograph of a car taking a corner hard, you will see that the weight of the car shifts in the opposite direction to the corner. The G forces will always throw the weight of the car away from the direction of turn, which in turn loads the suspension on the opposite side. That's why bikers lean into a corner, as the G forces are trying to throw the bike away from the turn in.

http://en.wikipedia.org/wiki/Car_handling

Weight transfer - the wheels on the outside of a curve are more heavily loaded than those on the inside. This tends to overload the tires on the outside and therefore reduce road holding. Weight transfer (sum of front and back), in steady cornering, is determined by the ratio of the height of a car's center of gravity to its track. Differences between the weight transfer in front and back are determined by the relative roll stiffness and contribute to the over or under-steer characteristics.

Posted: Tue Nov 06, 2007 6:00 pm
by MarkyB
You need to take the wheel off on the side the noise comes from and look for what is rubbing on what.
don't forget to look at the inside of the wheel rim.
Where rubbing has happened you normally get a rough surface with a sprinkling of fine iron filings each side.

Posted: Tue Nov 06, 2007 8:54 pm
by bmcecosse
Despite many answers -the original 'poster' seems to have disappeared after asking for help!
All the 'cure' efforts seem to have been (correctly) aimed at the pasenger front wheel which is the loaded wheel in a right hand turn.

Posted: Tue Nov 06, 2007 11:55 pm
by Kevin
I cannot for the life of me, see how a car can put the shifted weight onto the right hand wheel when turning right. If you look at any photograph of a car taking a corner hard, you will see that the weight of the car shifts in the opposite direction to the co
Right that has cleared that up then as I thought that only applied when driving and turning, whereas I read the post to mean it only happened when turning right and the G force would be non existant, so something else learned today and I will have to watch some cars turning tomorrow.

Posted: Wed Nov 07, 2007 12:04 pm
by Kevin
Well watched cars just turning right and even they lean to the left very slightly and yet I always felt it was the opposite probably because I tend to lean a little with the wheel when turning, so just goes to show what I though was happening at slow speed was the complete opposite, sorry if I have confused anyone else as much as I managed to confuse myself :oops: