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Wilwood (fixed caliper) not centered over rotor - problem?


turbogrill
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Hi,

 

I am currently trying to put on Wilwood on my car, I am not using a premade kit.

 

I managed to get the caliper on but the disc is not in the center/middle of the caliper. What would be the consequence of this? 

 

One pad side would wear out a little quicker? But functionally 100% correct?

 

 

 

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Take the caliper, install the brake pads and slip over the rotor. Position the caliper to where you want it to be. After removing the bleeder while using and air hose with an rubber tipped blow gun hit the hole with air. That will force the pads to clamp around the rotor while centering the caliper. Make bracket. 

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They usually include thin washers with the caliper bolt kits to help get the caliper centred properly. You can either shim or shave your bracket accordingly.

 

Do your best to get it in the middle, but as long as one pad isn't rubbing on the rotor when new and the caliper piston(s) is fully retracted you should be good.

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 The caliper pistons are just floating on brake fluid so it doesnt matter how close each side is to the rotor in terms of wearing down pads. when you hit the brake pedal it will put an equal amount of force on each piston in the caliper. Definitely try to center it as said above. 

Edited by Zimo
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They don't "float on fluid", they ride on a seal and are pushed by fluid.  Just sayin.

 

Center the caliper as best you can.  A mm or so either way isn't going to be a problem, but being offset 4mm could.  The disc pathways are spec'd for a specific width and pistons are designed to have set range.  Just like you don't want to put a 28mm wide disc in a caliper that accepts a 36mm disc.  The chance is if you were to get the caliper offset to one side too far, as the pad wears down (especially common in our series) the pistons could be pushed out farther than designed, cocking them in the bores or causing them to loose seal/fly out.  Get it as close to center as you can.  You can buy metric shims at mcmaster (don't just use flat washers, they're not "flat").

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  • Technical Advisory Committee

  ^^ what he said .. How much off 1,000s or 1/2 inch . Like said above the pads will wear equally but with caliper pistons on one side already out farther than the other, when the pads material wears the piston may come out past the seal and instant brake failure ..  Like I have said many times before a car that won't start is just a problem one that won't stop will kill ..   BRAKES = #1 thing to get right ...

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54 minutes ago, Bremsen said:

They don't "float on fluid", they ride on a seal and are pushed by fluid.  Just sayin.

 

Center the caliper as best you can.  A mm or so either way isn't going to be a problem, but being offset 4mm could.  The disc pathways are spec'd for a specific width and pistons are designed to have set range.  Just like you don't want to put a 28mm wide disc in a caliper that accepts a 36mm disc.  The chance is if you were to get the caliper offset to one side too far, as the pad wears down (especially common in our series) the pistons could be pushed out farther than designed, cocking them in the bores or causing them to loose seal/fly out.  Get it as close to center as you can.  You can buy metric shims at mcmaster (don't just use flat washers, they're not "flat").

I didn't literally mean Float as in buoyancy. Meant it as not settled in a definite place; fluctuating or variable. The fluid by itself isnt going to lock all the pistons in the exact same extended position.

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2 hours ago, Bremsen said:

They don't "float on fluid", they ride on a seal and are pushed by fluid.  Just sayin.

 

Center the caliper as best you can.  A mm or so either way isn't going to be a problem, but being offset 4mm could.  The disc pathways are spec'd for a specific width and pistons are designed to have set range.  Just like you don't want to put a 28mm wide disc in a caliper that accepts a 36mm disc.  The chance is if you were to get the caliper offset to one side too far, as the pad wears down (especially common in our series) the pistons could be pushed out farther than designed, cocking them in the bores or causing them to loose seal/fly out.  Get it as close to center as you can.  You can buy metric shims at mcmaster (don't just use flat washers, they're not "flat").

 

That is a good point!

 

It's missing 0.085", about 2mm.

 

With the way it's mounted now I can't use spacers, it needs to go more towards the wheel (away from the diff).

 

My options:

 

1. Grind of a little material on the caliper mounting point. Might be hard to get flush

2. Grind of a little material on the strut mounting thingy. Probably harder

3. Different Bracket/mounting.

 

EDIT:

My rotors are 0.36-0.37" thick.  Max is 0.38" min rotor is 0.25". So from the pistons perspective I am running my discs 0.015" below minimum disc diameter when the pad is completely worn out.

 

So essentially I might overextend the piston 0.015" if I run the pads all the way down. 

 

Edited by turbogrill
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 As long as the new pads slide in without a hammer. You should be fine.

 You can add shims at mount . If you know  of any old school Jaguar shop, the tech should have some in the top right crap drawer.

 Cut one side of the rotor. shim the rotor , skim the rotor mounting surface. 

 Grind the bracket

Grind the caliper mounts

 Hammer the bracket over a tad. then watch for un square Pad . 

 First. measure to the snugged disc from the near side of the bracket. Figure how much you need . Write it down.   

 If you do this, maybe you could knock the bracket closer to the wheel . Take the mounting bolts and weld a long piece of tube to . Square  the tube to the bolt  vertically in the BA vise with a pair of nuts. Spin the tube until it is square  to the bolt.  Now it should be long enough  to square the bolt  receiver to the axle /hub .

 Run the  now really long  bolt in with a jam nut against the bracket to snug.    Bend it carefully  to square.     Pull and tappy tap  the bracket gently .  A level may come in handy. measure from the snugged up disc. 

 Get a large sanding block and drag sand the bracket  surface that the caliper bolts to . Drag file it for finish .   A nice surface here is important ** the caliper must sit even and flush **  Blue locktite is your friend. 

 Double check the thing with the rotor snugged on with nuts and maybe a laser square. Close will work but the pads will need some bed time.  

Edited by flyinglizard
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I wonder what the manufacturing tolerance is for the axle, bracket, caliper, and rotor.  I bet way over 0.015” for everything.  

 

For the Ford to adapt rear T-Bird brakes to the Mustang we do the following:

Pull bracket off the outside of the flange.  

Cut C into the bracket so it will slip over the axle and mount inboard of the flange.  If the is any welding slag grind it off so the bracket mates to the flange.  

Mount everything up with the brackets swapped to the opposite side.  

Find out that where the rotor is supposed to slip on the axle hub the hub is too big.  With the car on jack stands start the car and put it in first gear.  Grab that grinder you used earlier and turn down the hub until the rotor fits on.  

Use your eyeball and shim the caliper to bracket with whatever washers you can find in the garage.  

Go race.  Have had it that way since 2014.  

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As mentioned, you might have trouble getting the pads installed on the short side.  With the disc suited pretty well to that caliper you will likely be fine as long as the pads fit and the disc still has a couple mm of clearance to the caliper pathway.  I'd still suggest trying to shift it over and center it better if possible (even if just 1mm)....but more with creativity than violence.

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