Anti squeal shims, bit of grease or not

[daverclasper]

HI

Seem to be conflicting views on this.

If yes, then I have white or copper grease. Which is better?, please.

Thanks, Dave 

[Guest]

Hello Dave,

I have always used Copper Ease on my shims and also a light smear on the back of the pads.

Also worth placing a light smear where the pads sit "top & bottom" in the caliper.

Needless to say, use sparingly.

Regards.

Richard.

[Pete Lewis]

Yes coppa slip is an antinseize paste  and temperature  stable    the white mechanical brake grease is not for pads  more for shoe adjusting levers and the like  in a drum brake,  it wont like the heat of disc brakes

As Richard says a light smear on the shim and pad backing  helps pad sqeal  ,  

Pete

 

 

[daverclasper]

Thanks for that.

I'm changing the pads and would like to push pistons out with the pedal a bit more to clean up, without popping out of seal.

Any idea, how much from front of caliper body bore , to top of piston, I can safely do this please.

Thanks, dave 

[Pete Lewis]

If the caliper is on car then remove the pads and fit a peice of plywoed halve the pad thickness , press pedal till the wood resticts travel and with wood removed you get enough piston extension to clean around it  , a gentle lever will return to fit the pads and shims 

Pete

[daverclasper]

Thanks Pete.

Caliper/s are still on car, though pads difficult to get out. Only tried one and got it half way out, levering with screwdriver through pad, pin holes.

Have a wear ridge on edge of disc that is snagging it I think. Will remove caliper by tapping  it off disc to pull out pads (unless there's a tip to avoid this).

Dave   

[AidanT]

Dave 

Assuming your pads are not new you should be able to push them back against the pistons to give more space. If they are difficult to move you can always make it a little easier by opening up the bleed nipple  Do remember to top up the brake fluid after though 

Aidan 

[Pete Lewis]

Can you not lever against the disc and pad to push the piston back into the caliper 

There is a minimum thickness for a disc , if its lipped you make be heading for some new discs.

If thinckess is ok you can grind the lip off   lips and grooves can make  for poor new pad bedding  in.

Pete

 

[daverclasper]

Thanks.

Have got pads off one side.  In the haynes it gives a max disc refacing of 0.5mm per side. I'm guessing the lips are at least that. Using micrometer the disc thickness is 11.3mm?

Cheers, Dave

[Pete Lewis]

triumph  ws manual gives 11.68mm as the min thickness  (0.460" )    so youre a bit on the thin side 

club shop are £29 a pair    but shop around  if you decide to get some new ones 

Pete

[Guest]

Dave,

Can you confirm your vehicle, please ??

Thanks.

Richard.

[daverclasper]

Thanks for that Pete. bye the way, hope you had a good holiday.

[Pete Lewis]

yes IOW  very sunny,  too many pub dinners , main? roads are all re tarmac  nice and smooth   but the towns are  really  double  awful.

[daverclasper]

Hi Richard. Vitesse Mk1 2Litre

Dave

[daverclasper]

Just a couple more questions please.

Brakes have always been very good on MOT's, since I've had it, with no pad dismantling done.

Just interested, as the outer pads on both brakes were more worn than the inners, though when I pressed in the pistons on the pedal (after pushing them out about 15mm from caliper ,cleaning up rust scabs and lubricating) with no interference from discs/pads etc, the outers  did not move in (though a bit of movement on them). Clamping the inners, then, outers will move in.

Is this normal?.

Also, there was some rust scabbing on the pistons, some going up about 15mm from piston front face (which I cleaned up).

Do the caliper bores also rust and therefore maybe the calipers not re-claimable? .

Thanks, Dave

   

[Pete Lewis]

calipers tend to be sort of plated/passivated ,    it doesnt last for ever 

corrosion can take hold 

Pete

[daverclasper]

Thanks Pete.

If the seals/bore fail, is it a case of slow weeping, rather than total loss of brakes, say when a M/C can go.

Dave

[Pete Lewis]

not had a failed one that leaks just come across some pretty seized ones 

think in general rears leak...... fronts seize  being in a poor environment 

juts thoughts 

Pete

 

[Gully]

I had a caliper piston seal begin to weep having disturbed it when changing a wheel bearing last year. Brakes continued to work fine, but noticed the leak down the inside of the tyre and onto the ground, so replaced both calipers. They were due a change or rebuild anyway, as the inner Pistons were slightly sticky - cleaned up the disc nicely both sides when braking hard, but in general use progressive braking the outer Pistons seemed to be doing all the work and the inside of the discs showed some corrosion.

Gully

[PeteH]

Hi

In Theory the effort is applied to both side of the disk equally, unless one piston is Lazy, when the lazy one acts more slowly. That will manifest as failing to come off quickly and heating up the brakes by dragging. Also happens a lot with sliding Calipers when they get Cruddy.

Pete