brake question

[reisertracing]

On my LD19 brakes I changed pads and re-used the cotter pins and safety wired them. I had heard afterwards that one shouldn't reuse cotter pins and use new ones.

How many of you re-use them vs new ones each time you change pads?

[D.T. Benner]

I reuse them it they are not fatigued at the bend point. You don't have to bend them very much as they only serve to retain the pad from radial movement. The caliper frame takes the loads. I don't know if anyone else has the problem of the edge of the pads hanging over the outside edge of the rotor on a late model Van Dieman? I cured that by using a small round file to open the cotterpin holes up to the next size cotterpin with the increased (filed out) part of the hole inboard into the caliper body. Now I get full contact with the pad and rotor!

[Purple Frog]

Not sure I have ever changed them. But then, come to think of it, cars only last me three years.

[JHaydon]

I think I've reused pins when I've replaced pads at the track. But replacing them in the garage, cotter pins are really not that expensive.

If you are going to reuse them, as DT points out, don't bend them all the way. Just bend them enough to keep them from falling (vibrating) out. And keep on safety-wiring them.

If you worry as much as I do, you may want to safety wire the pins to the caliper (or to the pad) rather than to the other pin, in such a way that the wire can retain a pin from falling out if the bent tang breaks off.

Or get REALLY silly and drill the small end for safety wire instead of bending them

[Dave SanF 50]

I reuse them, too, just be mindful of the bend where they WILL break over time. As DT and John both point out, don't bend the S*** out of them. Just a slight widening so they can't vibrate out. I also use SS pins I find at ACE. Seems the stainless will tolerate a whole lot more bending without breaking. Beware, they are heavier, so if unsprung and total weight are an issue, maybe consider some other solution, LOL
dave

[D.T. Benner]

See John-you can use stainless steel cotterpins and drill lots of tiny holes in them to make them lighter!! Just one more thing you can do in the winter to keep busy!

[EYERACE]

reuse a cotter pin? - that means you don't really try to keep a deep number of a fasteners assortment in your bins - i've done it but in general i won't anymore - and since i carry an assortment of fasteners to the track, i'll only reuse a cotter pin at the track if i'm out of that size - but i'd like to think the friendly parts/stuff/dealer trailer at the track has a nice assortment of fasteners too. ..........for lack of a nail the shoe was lost, for lack of a shoe the horse was lost, for lack of a horse the rider was lost......the message.....the battle......the war.............smith said it "prepare to win"

[D.T. Benner]

I only bend one leg of the cotterpin so every one is good for 2 sets of brake pads. In 20+ years I have never had a cotterpin break so maybe I should try harder to break them?

[Steve Demeter]

Think of how much a cotter pin costs.

Think of the cost if one fails.

I quit reusing them after reading that in one of Carroll Smith's books.

Just don't make sense.

Even if nothing is damaged and the only cost is a lost session or race, the cost is many many times that of a cotter pin.

[Scott Hanba]

Aircraft Spruce
1/8 x 2 $0.05 ea.

Order 100 of them and don't worry about it.

[Charles Warner]

Why bend them at all? Install from opposing directions and safety wire the heads to each other providing an inward restriction on both.

[DaveW]

HMMMMM...

I don't know if I should let all of you know just how cheap I am...

Since I change brake pads to a freshly machined set (I machine used ones so the surfaces are parallel) almost every session, I re-use the cotter pins until 1 of the 2 ends breaks off (or looks like it is ready to). Since I bend both ends of each pin ~45-degrees, 1 end is all that's really needed to retain the pin. When the first end of any cotter pin breaks off, I then replace all the pins with new ones.

[D.T. Benner]

Well it seems the "Mature" drivers like Charles and Dave have spoken! You know it's getting into winter when we have long discussions about cotterpins!

[Charles Warner]

HMMMM . . .

I wonder where the energy is sent more wisely? Always installing new cotter keys or taking the time to mill one's brake pads parallel? No Dave, not cheap. Prudent or frugal, OK - but definitely not cheap.

[Purple Frog]

Wait til you see Dave's brake pad spacers.
I even copied that idea and built a set.
At first it seemed frugal. Get as much pad life as possible.
But then I learned to answer was they were to prevent "piston cocking" when the pads got thin.
I would bet that Dave's cotter pins are custom made out of unobtainium at ICP and cost a bit more that $.05. Unsprung weight being such an evil curse...

[BGP]

Regarding brake pad spacers, couldn't you use an old set of pads backing plate? Or am I missng something here?

[DaveW]

That is what I use...

Froggy just made them sound exotic.

[John Robinson II]

re-use the pins till you break one. even if one pin, heaven forbid, did come out the other pin will keep the pads in the caliper. I now have a numerous pad spacers since I started having my pads ground back flat after a race weekend. On the LD-19 there is no where near as much material as the 20's. But then again, I replace the seals in the calipers after 3 events and dont use the dust seals. As mentioned above, if it is snowing outside and you have nothing else to do... run the pins opposite ways and safety wire the heads. Better yet, why not get some SS 1/8" bolts and just replace the pads with them.

Geesh, must be snowing up north...

John

[James Hakewill]

My Crossle has R-clips to hold in the pads on the LD19's - courtesy of the previous owner, and I've never had any problem with them.

It makes it very easy to pull the pads out before every race and measure the thickness, or to change pads.

The bends in the R-clips don't interfere with the motion of the pads, by the way - which does require a little bit of massaging of the clip if you get fresh ones.

Picture attached..

James

[Charles Warner]

Well it seems the "Mature" drivers like Charles and Dave have spoken! You know it's getting into winter when we have long discussions about cotterpins!

I'm just ticked pink to be included in any grouping with Mr. Dave.

[formulasuper]

Regarding brake pad spacers, couldn't you use an old set of pads backing plate? Or am I missng something here?

I made aluminum pad spacers to save weight. The used steel plates are way to heavy!

[DaveW]

I made aluminum pad spacers to save weight. The used steel plates are way to heavy!

There are 2 reasons to use pad spacers as the pads get thin:
1. less heat transfer to the pistons than if just a thin pad were there
2. less piston extension (results in pistons staying cleaner, and less piston cocking).

One of the advantages of using old backing plates (which have pad-retaining holes) instead of aluminum for spacers is that they transfer less heat to the piston.

[kea]

Dave W,
Those KFP brake pads I gave you at IRP, have a ceramic heat shield between the friction material and the metal backing plate.
This is why Mark, Bill and others don't have a heat transfer issue.
Keith Averill

[DaveW]

Keith,

Actually, I've never had a caliper or fluid (Castrol LMA) heat problem. The spacers are a preventive measure as I stated above. I'd still use them to keep the pistons retracted.

I still have those pads - just have never had a chance to try them.

[Douglas Brenner]

Has any one pressure bled their brakes?? Vacuum bled?

[MarkM]

I use that Mityvac bleeder, the large one with the adapter that has a brass valve to control the vacuum. Works well for me, and my wife is really glad I got it.

[Mark H]

There was a post on this a few weeks back but, on street cars there have been both types come and go. The type that goes on top of the master cyl and pushs the fluid through (pressure) is a mess and can blow out the master cyl seals. The type that sucks fluid from the bleeder (vaccume) works about 1/2 the time, I have one of those its called a Vacula .

The only way that I trust is the tried and true 2 man system.

New carter keys and safety wire is the way to go on the pad retaining question.

Maybe a question like how to set-up brake bias would warrent a page but the life and times of a carter key??? It must be the off season.

[D.T. Benner]

I think one of the advantages to the Mityvac is that you are not forcing the piston and orings of your master cylinders past the NORMAL operating range of travel like you do with foot pumping them. Like making pasta sauce we all have our own way of doing things! You just have to go with what makes sense to you.

[marshall9]

What would be the disadvantage of just swapping the pads around, within the same caliper, to keep them wearing true? Might be a little different for a few laps, then they would be like new, only without having to cut them in?

[Paul LeCain]

I don't know the down side in an FC. We swap them in an FA all the time. They are different for a lap or two, but that's all.

[marshall9]

That's what I am thinking, It isn't much money to grind them back true, but my prep time is short, and by the time I take 'em out, blah blah....well you get the idea, it becomes like national engine effort, one being rebuilt, one in the car, one ready to go in, etc.....

[Bill Hetzel]

Doug, I made a pressure bleeder years ago out of a plastic garden sprayer from HD. I took the spray handle and nozzle off and replaced whem with some 1/4 inch plastic tubing. I took an old master cyl. cap and put a tube fitting in it. There's your pressure bleeder for about $15.
To use it, I fill the m/c up almost to the top, put the cap on and with about 5 pumps you can bleed both fronts or rears. This way you don't have any brake fluid sitting in the pressure bleeder for a long time, there is no moisture added by pumping the plastic "compressor" and you can bleed the m/c down to the level you want with no mess.
We also found some neat, little bleeder bottles at Harbor Freight that have magnets on the bottle. We stick them right on the brake discs ans the hose has a pointed, plastic fitting that goes inside the ID of the bleeder screw rather than over the outside - less mess.

[Charles Warner]

Good idea on the pressure bleeder. Only thing I see is that it can not be used to bleed the master cylinder itself. That can be critical on some cylinders (Tilton for one.) I still recommend the spring loaded bleeders. Been using them for years and these, coupled with the Harbor Freight mini bottles, makes bleeding a non-event. Open the bleeders,`connect the tubes, and move the brake pedal by hand.

[Roger Eade]

I use a long hose, back to the master reservoir, just keep pumping until you lock off the bleeder on that piston, then move to the other side, you do loose a little fluid on the first bleed to fill the tube and you need to top the reservior, but just nip the end of the tube when moving to the next bleed nipple and master cylinder, means you can pump as much as you like, aslo as you don't pump it at 100mph, you don't get air bubbles and get real good pedal, and don't use heaps of brake fluid.
Roger

[Brian]

I feel so inadequate in how I bleed brakes. All I have done for years is put a little anti-sieze grease on the bleed screw threads (to keep air from getting in and so the bleed screw doesn't sieze), attach the hose so that it goes up before it goes down to the bottle, crack the fitting, stroke the pedal quite slowly, stop when the air bubbles are gone, and close the fitting. Do all four and I have high firm brakes. Every time. I don't need a partner (except to maybe chat with so I don't get bored), I don't have a fancy system, I don't pump up pressure and crack the fitting. Is bleeding brakes this way wrong?

Brian

[DaveW]

What would be the disadvantage of just swapping the pads around, within the same caliper, to keep them wearing true? Might be a little different for a few laps, then they would be like new, only without having to cut them in?

That works for the leading/trailing edge wear, but does nothing for the extra wear on the outer edge due to more rotor velocity. Eventually, they get tapered even if you swap them.

[Tim FF19]

Back when I was helping with a very fast GT-1 car, I was shown how to cut material off of the pads so that the remaining pad wore evenly. On a big heavy car like that, taper was a big problem and trimming the pad material made all the difference in the world. I never bothered to do it on my FF because the taper was never very severe. However it should work with our little pads as well. I just end up doing what DW does, machining the pads flat after each weekend.