TRExp

Spitfire & GT6 Forum

Brake Caliper Pins

Moss Motors
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor

N5329K Avatar
N5329K Silver Member Robin White
Pacific Grove, CA, USA   USA
I just installed new pads up front. Do the pins need any lubrication?
Thanks,
Robin

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
cmfisher4 Avatar
cmfisher4 Gold Member Chris Fisher
Mystic, CT, USA   USA
Robin, I didn't lubricate mine and I don't remember reading about it in the workshop manual. I believe that the design has these only there as alignment and locating pins, though the pads do slide on them, I guess. But, I think the lube may be another thing to collect road dirt that may collect around the pads and potentially contaminate them, and may even cause the pads to stick in the "gunk".

Of course, I could be wrong...

Cheers,
Chris



I learn something new every day...especially if I am working on my LBC!
Please visit my blog and website at http://www.roundtailrestoration.com



Edited 2 time(s). Last edit at 2018-02-12 12:05 PM by cmfisher4.

N5329K Avatar
N5329K Silver Member Robin White
Pacific Grove, CA, USA   USA
Thanks. I kind of thought that might be the case. BTW, for those who haven't done it before, it takes a fair amount of push to get the pistons moved aside but it's an otherwise easy job.
Robin

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
clshore Carter Shore
Beverly Hills, FL, USA   USA
In reply to # 1512966 by N5329K Thanks. I kind of thought that might be the case. BTW, for those who haven't done it before, it takes a fair amount of push to get the pistons moved aside but it's an otherwise easy job.
Robin

The fluid displaced by pushing the pistons back into the calipers winds up back in the brake reservoir.
So you should take care that the reservoir is vented, and also that it does not overflow, and spill onto your scuttle, where it will ruin the paint.
Yes, I know DOT 5 will not 'eat' the paint, but it WILL create silicone contamination that is very difficult to remove, should you ever desire to
paint any contaminated area again.

A simple turkey baster is an easy way to remove some excess fluid before you push the pistons back.
(Hint: Do NOT use the one from the kitchen! Else if you DO, replace it with a new one ASAP)

N5329K Avatar
N5329K Silver Member Robin White
Pacific Grove, CA, USA   USA
Yep. I took out about 1/2" of fluid with an ear bulb and left the cap cracked a bit to relieve pressure. It still took a serious amount of pushing to move the piston. On the other hand, I noticed (first time) that I have drilled and slotted rotors. They're pretty, but I'm not sure they add much to the stopping power of a daily driver.
Robin

clshore Carter Shore
Beverly Hills, FL, USA   USA
The ear bulb works better than a turkey baster.
It allows little or no fluid to dribble back out after you have sucked it up from the reservoir when you are transferring it to a disposal container.

Smithisretired Avatar
Smithisretired Michael Smith
Wells, ME, USA   USA
In reply to # 1512972 by N5329K On the other hand, I noticed (first time) that I have drilled and slotted rotors. They're pretty, but I'm not sure they add much to the stopping power of a daily driver.
Robin

The drilled and slotted rotors add nothing to the stopping power of the daily driver and one might make the case that, if anything, they reduce the stopping power of any car by virtue of the fact that friction surface has been removed. What the drilling does is remove unsprung weight, making for better handling.

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
clshore Carter Shore
Beverly Hills, FL, USA   USA
The braking force generated is basically independent of changes in contact area of the pad and rotor.
The force and the thermal energy created by the friction depends on the coefficient of friction, and the clamping force of the pad against the rotor.
But what does change with area is the temperature at the contact site, less area yields higher temperatures, which can raise the pad material past it's breakdown point,
and also cause material loss at the surface of the rotor.

There is also the matter of the gasses created when the pad gets very hot.
Those gasses emitted at the surface of the pad can form a layer that 'lubricates' the region and effectively reduces the coefficient of friction.
It's claimed that the slots (and to a lesser extent the cross drilled holes) provide an escape for the gasses, reducing the effect.

The cross drilled holes are claimed to provide 3 functions:
1) When done properly, they are oriented and angled in such a way to provide an air pumping action as the rotor spins, and the air flow
through the holes cools the core of the solid rotor, which would otherwise only shed heat at it's flat surface.
2) The holes increase the overall surface area of the rotor, helping to shed heat more effectively.
3) The holes provide escape for the gasses from the pad (as described above).

All this works great for a racecar, where the rotors will run red glowing hot, and getting rid of the heat is job one.
The rotors and pads are considered consumables just like fuel and tires.
Racecar brake inspection & maintenance intervals may be as short as a few hours to a few dozen hours.
So when the inevitable cracks begin to form at the cross drilled holes, replacing them is an expected event.

Street cars ... not so much.

Now, you may claim that your street car brakes are never used as hard or as frequently as a race car.
Very likely that is true.

So WHY IN BLAZES DOES ANYONE FIT CROSS DRILLED ROTORS WHEN THEY ARE NOT NEEDED ?

I suspect that the answer is 'Bling', automotive jewelry.
(The vendors are more than happy to sell them at a fat markup.)

And if true, that's just fine, to each their own, our cars are often a means to make a personal statement.

But no one should buy into the line that they are 'for better braking' or 'better performance'.

Doug in Vegas Avatar
Doug in Vegas Douglas D
Las Vegas, NV, USA   USA
In reply to # 1513030 by clshore So WHY IN BLAZES DOES ANYONE FIT CROSS DRILLED ROTORS WHEN THEY ARE NOT NEEDED ?

Betcha most customers thought they could make them stop when rotors had nothing to do with why they flew into a bus stop.

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
N5329K Avatar
N5329K Silver Member Robin White
Pacific Grove, CA, USA   USA
They're too pretty to put into the DPO "improvements" bin. Let's call them, "They probably won't hurt much."
Robin

clshore Carter Shore
Beverly Hills, FL, USA   USA
In reply to # 1513171 by N5329K They're too pretty to put into the DPO "improvements" bin. Let's call them, "They probably won't hurt much."
Robin

I agree, kind of like minilites on a Pinto.

Doug in Vegas Avatar
Doug in Vegas Douglas D
Las Vegas, NV, USA   USA
In reply to # 1513175 by clshore
In reply to # 1513171 by N5329K They're too pretty to put into the DPO "improvements" bin. Let's call them, "They probably won't hurt much."
Robin

I agree, kind of like minilites on a Pinto.

No.

That one hurts a LOT.

. Hide banner ads & support this website by becoming a > Gold Supporting Member <

To add your reply, or post your own questions




Registration is FREE and takes less than a minute!


Having trouble posting or changing forum settings?
Read the Forum Help (FAQ) or contact the webmaster





Join The Club

Sign in to ask questions, share photos, and access all website features

Your Cars

1974 Triumph Spitfire 1500

Text Size

Larger Smaller
Reset Save

Sponsor Links