Brake caliper weights

Today I did some weighing of some calipers, maybe this is a thread already - if so, Im sorry. But thought it'd be cool to have a depository of information

First is a 93 (should be) 300ZX - 9lb 15oz..so right at 10lb
Next is a LS430 - 8.5lbs
Those two are both made by Sumitomo
Last is a Brembo caliper off of a ML55 Mercedes, 10lb 2oz
These were weighed without any pads or hardware (the pins and flat metal piece)

I have the rear off of the MB, but did not weigh them because I dont have any rears to compare. And I dont have my 91turbo brakes off of the car, maybe one day I can weigh them.

There's another dimension to brake calipers - stiffness. For some cars it won't be an issue, but with others it can be, depending how high the brake line pressure is. Way back when Nissan/Datsun raced sedans, sometimes they had to "downgrade" the brake calipers back to steel in order to prevent caliper flex, felt as a soft pedal.

You know, just to complicate an otherwise seemingly simple thing.

I've run a Wilwood caliper that wasn't stiff enough (Dynapro 6, not to be confused with the 6A that replaced it). It was unnerving, with lots of pad knockback. On certain corners on track, I had to apply the brakes twice. 

Caliper stiffness is a legit concern. 

Keith Tanner said:

I've run a Wilwood caliper that wasn't stiff enough (Dynapro 6, not to be confused with the 6A that replaced it). It was unnerving, with lots of pad knockback. On certain corners on track, I had to apply the brakes twice. 

Caliper stiffness is a legit concern. 

Interesting, Keith.

I raced with Dunlop calipers on my MGA Twin Cam (same as used on many Jags) and pad knock back was a serious issue - so much so that on ever straight I used my left foot to bring the pads back up near the rotor (I had a dash light that lit when the brake light switch did - just before enough pressure was applied to start actually braking the car). We always figured that it was end float on the rear end hubs that did it - the first car that ever used those calipers front and rear, the Jensen 541 Deluxe (in 1956) experienced the same problem.

Not a big issue on the street but cornering on the track sure had an effect.  I never thought it was caliper flex as I don't think that was an issue with the Dunlops, but who knows....

In reply to wspohn :

My Black Jack had the original Dunlop brakes.  Never had a single problem.  Come into a tight corner at 150 and step on the brakes hard. I could feel my eyeballs want to pull out  and it took all the neck strength I had  to keep my face from flopping down.  
    Most cars I was way out braking A few could stay with me but no one could out brake me.    
Lap after lap on the 4 mile long brake torture test of Elkhart Lake.  No other track is as hard on brakes.  
I wonder why you had problems?  

In reply to wspohn :

Normally knock back is due to wheel bearing problems. But these calipers exhibited the exact symptoms of knock back, and changing to the 6A with no other modifications cured it.

It's not a reassuring feel, is it :)

Pad knock-back implies just that - that something is physically pushing the pads away from the disc:

• As suggested, axle end play
• Loose caliper bolts
• Wheel/hub deflection
• Irregularities of the disc surface itself

Needing to press the pedal twice does sound like pad knock-back, but not flexing calipers. Flexing calipers would produce a spongy pedal every time, and wouldn't get cured by pressing it a second time.

I agree, it doesn't match what's supposed to happen. But the behavior was definitely there, and I know it wasn't another component or a mechanical issue. It was clearly related specifically to the calipers as I didn't change anything else.

Wilwood also pulled that caliper from the market as soon as the 6A was introduced. The difference was a big cast bridge. 

In reply to Keith Tanner :

The Jag XK150 with rear disk brakes had pretty tight  axle float.  I can't remember off the top of my head what year the MGA twin  cam was made.  The XK150 came out in 1958 but the disk brakes on the D type came out in 1954. So I suppose they already had that sorted out.