Handbrake (Yes sorry again)

[Grizzly]

Caliper is definitely not centred, i fitted a pair of brand new identical main pads and pushed the pistons back to find there is quite a difference in gap between the pad-disk inboard-outboard....... So after butchering some feeler gauges (only had metric i was prepared to murder) it seems i have 2x 0.9mm spacers missing.

After a quick look through our washer guys catalogue the closest i could find is 7/16x0.032 thick (approx 0.8mm thick) so i'll get some and see if it helps. I know it doesn't sound allot but just that will mean the inboard pad isn't dragging when i set the pads to more or less the correct clearance (i hope)

[billwill]

I don't think that the pad lifters (centralising strips) are meant to be springy, I think they are just mild steel.

The idea is that you bend them outwards when you fit new pads then as the pads are used up the lifters gradually bend back inwards again, with the small amount of springiness just right for lifting the pads off the disk. The total movement over the lifetime of the pads is such that spring steel would probably break.


A good idea though is to fit a coiled compression spring on the adjusting rod so that it pushes the levers apart when you release the brake handle. (ah I see you describe that anyway)


As for your hope of not needing to adjust it for a year or so, that's not going to happen, you will need to readjust the handbrake after the handbrake pads have bedded in.

[rgh0]

There are no washers.

If the disk is central for the main caliper but not for the handbrake caliper then the problems is with the handbrake assembly. The handbrake caliper arms need to be pulled back evenly from the disk by adjusting the L shaped spring arms

If the disk is not central in the main caliper then you need to investigate why the hub / axle / disk assembly had ended up in the wrong location.

cheers
Rohan

[Grizzly]

Ok found the issue, my new brake disks are not correctly machined. The centre of the brake disk (where the three bolts go through to secure) is thicker than the original one it replaced, it's a bit difficult to measure on the car but it looks like thats where my problem is.

Teach me for not checking the disk more thoroughly before fitting. Thought it would be correct coming from one of the Specialists.

[john.p.clegg]

But surely the pistons and handbrake pads are floating and should take account of any offset , it is only less than 1mm ?..

John

[Grizzly]

I don't think that the pad lifters (centralising strips) are meant to be springy, I think they are just mild steel.

The idea is that you bend them outwards when you fit new pads then as the pads are used up the lifters gradually bend back inwards again, with the small amount of springiness just right for lifting the pads off the disk. The total movement over the lifetime of the pads is such that spring steel would probably break.

The way i understand it... when you bend a piece of metal you get Spring back, so if you are bending sheet steel you have to take the Spring back into account to go past and let the spring return you to the degree you intended.

The Centralising strips use this Spring back to lift the pads back off the disk, they have X amount of movement during spring back that isn't permanent and will return to their original shape. The problem i found with my original strips is that there was little to no Spring back because i suspect they had gone soft with age/use. So when i bent the strips square and fitted them the would flex with the Pad movement but instead of having some return to their original shape the bend would be permanently causing the pads to drag.

[Grizzly]

But surely the pistons and handbrake pads are floating and should take account of any offset , it is only less than 1mm ?..

John

The main brake isn't really an issue because that finds it own centre but the handbrake Centralising strips are bolted to the caliper and no matter how much i try to bias them it always tries to lift the outboard handbrake pad off first (so the outboard pad needs to be 2mm off the disk before the inboard pad is clear, which isn't too hot if your target clearance is 3 thou 0.8mm, but if i add a 1mm shim to the caliper-hub mount it would centralise that 2mm making things much more even)

The Inboard pad may not be putting any load on the disk but it's dragging constantly unless the adjustment is backed right off

All that said, i'll see if i can find some better fitting disks which should fix my centralising issue.

[john.p.clegg]

Take the centralising strips off place them in a vice and adjust them to the right shape with your lump hammer...

John

[billwill]

I find that the centralising strips have to be bent past "Square" for new pads. To about 110-115 degrees.

As I said above, as the pads wear down they permanently bend over time and when the pads are too thin for further use you will find that the strips are down to about 80-85 degrees.

That way the "spring-back" that you describe remains roughly constant. If the strips were spring steel they would not take a permanent bend and so the effort on the handbrake handle would increase as the pads wore down.

[Grizzly]

This is the perfect shape strip for a new pad (the shape they come new)

If you take any bit of Mild steel and bend it backwards and forwards for long enough it will start to fatigue. I know every one says you can reshape them but honestly comparing my new ones to the old ones (taking into account my car has only done 40,000 miles) i wouldn't bother for the ?6 they cost to replace (make a huge difference if you have the original ones still fitted)

[mbell]

I had problems with the pads not being central on mine and turned it to be the arm movement limiting/idle tab (can't remember the correct name!). It's the little metal tab on the arm the hand brake rod operates.

Adjusting/bending that allowed me to centralised the pads. Probably not this but with worth checking.

[Grizzly]

Does anyone know what the correct size of bolt secures the Handbrake umbrella to the body?

I strengthened the area the bolt goes through on the body next to the throttle cable so even though i kept the correct position i lost the hole size. Looking at the umbrella mechanism the bolt size appears to be 9/16 but that takes the bolt head quite tight to the Bulkhead (if i drill the hole exactly where i left the witness mark). If it is 9/16 should it have a captive nut inside the car as there is no space to get a spanner etc on.

So i thought i'd ask before i make a mess

[john.p.clegg]

Mark
I used a M6 roofing bolt along with the square nuts that come with them,the square nut traps itself and doesn't rotate and the job can be accomplished with just a screwdriver...

John

[Grizzly]

Just had a crawl under the dash of my +2, the Handbrake Umbrella on that seems to be held up by a self tapping screw and Spire clip? I guess that would make sense why the hole in the bracket is so big while the hole in the Body seems to be very close to the corner (seems like the head of the fixing is quite small).


Just for reference, the Umbrella Mechanism is held up with a 1" long N0.14 Hex headed screw and a spire clip.

If anyone needs one pm me as i have loads of them (could only buy them in a 20 pack )

[Grizzly]

Just an Update.... I have had all sorts of problems with the rear brake disks, i've had three sets of different makes and none fit perfectly central. So i've had some taken off the original set to centre them and i've been able to set the clearance up to a paper thickness without any dragging which was nearly worth the aggravation.

Typically i've just gone to set the Cable up so the tree lever is nearly touching the Chassis tube and for some reason it's a good inch away with the adjustment right in (might have to take a bit out of the Cable sleeve) but even so it locks the back wheels in the workshop from about 10mph with four clicks (on brand new Summer tyres) never had that with my +2.