the curse of kelsey-hayes

paolo_mangusta · Post by **paolo_mangusta** » Mon Aug 06, 07 7:53 pm

Typical - after all the time sitting while I sort the discs and hubs out and try and make some sense out of all my duff engine purchases, the calipers are rusted up and the pistons are all crapped.

So I'll rebuild them I think... both four-piston calipers. After all, they must work ok once sorted, four-piston calipers are what fancy modern cars have isn't it?

So the only place that has the pistons in stock has just got back to me.

They've got the pistons... SEVEN of them and don't think they'll get any more

Sorry just had to get that off my chest, I swear these brakes have been sent to punish me

TrevD · Post by **TrevD** » Mon Aug 06, 07 8:09 pm

if your realy stuck i can reproduce the piston (or all 8) in stainless. i will need an original as a pattern.

paolo_mangusta · Post by **paolo_mangusta** » Mon Aug 06, 07 8:31 pm

wow, that's pretty impressive. I'll have a think what I'm going to do but that might be a solution, cheers

I do know I wish I'd not bought a car with these brakes...

And I know that unless I replace them all the pistons will play up again.

And that even if I could afford these:

http://www.stainlesssteelbrakes.com/pro ... &year=1972

then I wouldn't be sure that I would be able to get seals etc for them in time to come so I'm not sure they'd be a good idea long term

And they don't even make you go faster

latil · Post by **latil** » Mon Aug 06, 07 9:22 pm

Early Mustangs up to 67 used K/H 4 pot set up. Of course,they're not the same size are they? Just a thought.

paolo_mangusta · Post by **paolo_mangusta** » Mon Aug 06, 07 9:54 pm

I thought they were, but now I'm not so sure since I'd have thought they were easy to get if they were, since everything for Mustangs seems to be available. I'm off to look up part numbers...

paolo_mangusta · Post by **paolo_mangusta** » Mon Aug 06, 07 9:59 pm

Dorman part numbers are 502S for the 'Stang, 501S for the Dodge, don't know what the difference is but too risky when I can't send them back.

latil · Post by **latil** » Mon Aug 06, 07 10:04 pm

Early Camaro too.

paolo_mangusta · Post by **paolo_mangusta** » Mon Aug 06, 07 10:30 pm

This lot look ok, and somehow it's cheaper for them to ship back two complete calipers than Rock Auto could ship the pistons inside them.

http://www.calipersonline.com/

Going to see how much it is to send the cores back though as they charge $100 core charge each

latil · Post by **latil** » Mon Aug 06, 07 10:48 pm

If you have or can get the seal kits it would probably be more cost effective to have new pistons made here.

Mick · Post by **Mick** » Mon Aug 06, 07 11:03 pm

I think i've got some and that kit wont fit your car as far as i know, most kits are made for the drum spindles, kh are quite rare, so there's not a lot of money in kits for them.
You would need drum spindles, 9" are best.
Mick

paolo_mangusta · Post by **paolo_mangusta** » Mon Aug 06, 07 11:20 pm

Hi Mick

According to the page, that lightweight caliper kit is only for the cars that already have the K-H calipers. I looked at the kits on offer when the discs wore out, but stupidly tried to keep it original, because I thought the K-H option was rare and worth having, because the aftermarket kits needed big bolt pattern 15" wheels and I'd just bought some new tyres and found some SBP rallye-type wheels. And now I've got brand new discs and bearings so want to stick with the spindles and hubs I've got even more

Long-term I suppose the sensible thing to do would be to find some calipers off a big BMW or something and have some adapters made, that way at least I'd be sure of a decent supply of bits... not sure it's worth the grief though

You've got seal kits you say? I'll bear that in mind when I've done all my sums

Cheers

Paul

charger01 · Post by **charger01** » Tue Aug 07, 07 12:00 am

Kelsey- Hayes Disc Brake Specifications
Piston Diameter 1-5/8"
Piston bore diameter1.636"
Piston bore diameter Maximum Allowable (AFTER HONING) 1.638"
Piston seals .092" Wide .100 Radial thickness
Braking Disc
Type Ventilated cast iron
Diameter outside 11.04"
inside 6.91"
Disc runot (max allowable) .0025"
Disc surface finish 15 to 18 micro inches
Disc thickness .810"
Brake shoe & lining
Type > bonded
lining thickness .400" (nominal)
width 1.84"
length 4.82"
braking area 8.50sq In./segment

JohnR · Post by **JohnR** » Tue Aug 07, 07 12:04 am

Got KH brkes on the barracuda fixed mine with rear pistons from 1981 rear range rover caliper just a tad short of 1 5/8 and you have to cut a groove for the dust boot and use the KH seals but they still work after 4 years and the range rover pistons are much cheaper and easy to get hold of

charger01 · Post by **charger01** » Tue Aug 07, 07 12:05 am

Tightening Reference
caliper mounting bolts 45-60 ft/pounds
caliper assembly bridge bolts 70-80
disc splash shield bolts 17" lbs
caliper bleed screw 100" -pounds
brake tube fitting nuts to proportioning valve 85" pounds
wheel assembly to front wheel hub and disc assembly nuts 55

Hope this helps

Dave999 · Post by **Dave999** » Tue Aug 07, 07 11:07 am

bet trevs pistons will be a better fit than any mass produced production line tollerance aftermarket dooberry

dave