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the curse of kelsey-hayes

Posted: Mon Aug 06, 07 7:53 pm
by paolo_mangusta
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 :roll:

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

Posted: Mon Aug 06, 07 8:09 pm
by TrevD
if your realy stuck i can reproduce the piston (or all 8) in stainless. i will need an original as a pattern.

Posted: Mon Aug 06, 07 8:31 pm
by paolo_mangusta
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 :D

Posted: Mon Aug 06, 07 9:22 pm
by latil
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.

Posted: Mon Aug 06, 07 9:54 pm
by paolo_mangusta
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...

Posted: Mon Aug 06, 07 9:59 pm
by paolo_mangusta
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. :(

Posted: Mon Aug 06, 07 10:04 pm
by latil
Early Camaro too.

Posted: Mon Aug 06, 07 10:30 pm
by paolo_mangusta
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 :shock:

Posted: Mon Aug 06, 07 10:48 pm
by latil
If you have or can get the seal kits it would probably be more cost effective to have new pistons made here.

Posted: Mon Aug 06, 07 11:03 pm
by Mick
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

Posted: Mon Aug 06, 07 11:20 pm
by paolo_mangusta
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

Posted: Tue Aug 07, 07 12:00 am
by charger01
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

Posted: Tue Aug 07, 07 12:04 am
by JohnR
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

Posted: Tue Aug 07, 07 12:05 am
by charger01
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 :thumbright:

Posted: Tue Aug 07, 07 11:07 am
by Dave999
bet trevs pistons will be a better fit than any mass produced production line tollerance aftermarket dooberry

dave