Solid Brake Bushings - rules change for 2006?

#1

Talking to Carter & Steve Kapuchansky two weeks ago, I realized that I did make a non-compliant modification to my coupe – I installed solid guide bushings in my ATE front calipers. :pinch:

Carter suggested that it could be a consideration for a change to next year’s rules, so I figured this was the best place to discuss it. (Note: I am only talking about solid brake bushings in this thread, not any other ‘illegal’ solid bushings or mounts).

Now, before I make my case, there is one point – the mod is not nearly as irreversible as I thought – p/n 34 11 1 157 038 is a dealer kit to repair/replace the rubber guide bushings (~$30 per axle)…

So here’s my case:
[ol][li]The solid brass bushings are ~$50 per axle from BavAuto, BimmerWorld, TMS, etc – they’re not prohibitively expensive or exotic.[/li]
[li]The kits only work on the ATE calipers, which have rubber guides; the Girling calipers have a solid guide design, AFAIK. The ATE calipers were mostly used prior to 1988, but there is some evidence that they were used sporadically in the 1989-1991 cars. [/li]
[li]The solid bushings ensure that the pad evenly contacts the rotor surface, for even wear and a more consistent pedal feel.[/li]
[li]SCCA & BMWCCA CR approved, according to TMS.[/li]
[li]They permanently replace a rubber wear item.[/li]
[li]As far as I can tell, (I haven’t yet tested), they fit the ATE rear disc brakes that are common across the E30 line.[/li]
[/ol]The part replaces #12 on the ATE caliper diagram below:

Here’s a shot of the bushings (with guide pins):

:whistle: Just food for thought. If this is an inappropriate topic/time, let me know and I’ll delete the thread.

Post edited by: sharkd, at: 2005/10/07 13:20

#2

Rob,
This is the right place to talk about these suggestions.

I really like the idea behind these pieces, and I’ve considered buying them for my street M3. I think they could help uneven pad wear on the Spec E30, which I do get.

I’d like to present a thought - and this follows a discussion I had with an engineer friend of mine who is thinking of joining Spec E30: Our discussion centered around using metal "bushings" in other places. These could still be considered "bushings." Brass is a bushing material - it flexes, just less than rubber.

I guess the question is whether metals bushings are considered bushings, and not solid pieces.

The rules also don’t address replacing the brake guide pin bushings either. Since they don’t add a performance advantage, and if they are considered "bushings" then I think they’d be ok.

Post edited by: victorhall, at: 2005/10/07 13:57

#3

I think these are a great idea myself…

But I’d love to see that flexy brass bushing material you are dreaming up.

Can I have a hit of what you are smoking?

B) B) B) B)

#4

30SpecE30 wrote:

[quote]I think these are a great idea myself…

But I’d love to see that flexy brass bushing material you are dreaming up.

Can I have a hit of what you are smoking?

B) B) B) B)[/quote]

Yo mon, don’t forget ta be sharin’ da herbs with the racers out here in california!

I think this may be pushing the envelope of what falls into the "bushing" bucket. Or bowl, as the case may be. :lol:

Sorry, couldn’t resist on a monday morning. Seriously, I think that this is a change that should be considered. After all, the spirit of spec e30 is to provide participants with fun, low-cost racing. At $50 per axle, my guess is that this could pay for itself in a season by extending pad-life.

Post edited by: sdais, at: 2005/10/10 13:04

#5

The big problem is that they are ONLY available for the ATE calipers. To replace the Girlings with ATE’s is like 150.00 each then the bushings.

#6

Vic:

Tell your pal that I hope he will join us in Spec E30 but that he will be watched VERY closely.

Anyone who thinks brass is a flexible material is really stretching it. :laugh:

At Spec E30, we will consider (but won’t always adopt) ideas that will save our drivers money and that make the cars more reliable.

However, we have to be very careful not to allow something that will, or even might, give one car an advantage over another.

Let’s talk about it at Summit this weekend.

Carter

#7

Yes lets discuss, the cost difference is about $100 per calp. plus the cost of the brass bushing.

#8

Honestly, I’m not familiar with the Girling calipers – from the ETK diagram, they look like the guide pin is held in place by solid material. If the Girling doesn’t use a solid guide bushing, then it isn’t fair, and I’ll withdraw my argument, as far as front calipers go.

Post edited by: sharkd, at: 2005/10/12 09:21

#9

The Girling pins are solid, but they have quite a bit of play as well. I still get and "angled" wear pattern on my front pads. The hot ticket is to swap to ATE calipers and run the solid bushings from Bimmerworld, but it isn’t legal for this class.

#10

sdais wrote:

[quote]30SpecE30 wrote:

[quote]I think these are a great idea myself…

But I’d love to see that flexy brass bushing material you are dreaming up.

Can I have a hit of what you are smoking?

B) B) B) B)[/quote]

Yo mon, don’t forget ta be sharin’ da herbs with the racers out here in california!

I think this may be pushing the envelope of what falls into the "bushing" bucket. Or bowl, as the case may be. :lol:

Sorry, couldn’t resist on a monday morning. Seriously, I think that this is a change that should be considered. After all, the spirit of spec e30 is to provide participants with fun, low-cost racing. At $50 per axle, my guess is that this could pay for itself in a season by extending pad-life.Post edited by: sdais, at: 2005/10/10 13:04[/quote]

Doh!! I checked while changing my front pads last night and noticed that I have the Girling calipers. I guess I’m just used to buying the ATE rotors so the name was familiar. Please strike my previous comments!

Anyone have any thoughts on whether either the ATE’s or the Girlings have any advantages over the other? Just curious.

#11

sdais wrote:

[quote]Doh!! I checked while changing my front pads last night and noticed that I have the Girling calipers. I guess I’m just used to buying the ATE rotors so the name was familiar. Please strike my previous comments!

Anyone have any thoughts on whether either the ATE’s or the Girlings have any advantages over the other? Just curious.[/quote]

I don’t think that it matters if you use ATE rotors with girling calipers… they’re the same dimensions.

#12

sharkd wrote:

[quote]sdais wrote:

[quote]Doh!! I checked while changing my front pads last night and noticed that I have the Girling calipers. I guess I’m just used to buying the ATE rotors so the name was familiar. Please strike my previous comments!

Anyone have any thoughts on whether either the ATE’s or the Girlings have any advantages over the other? Just curious.[/quote]

I don’t think that it matters if you use ATE rotors with girling calipers… they’re the same dimensions.[/quote]

Both ATE and Girling were/are OEM for BMW. Some cars got the ATE calipers and some(most I Think) got the Girlings. They are effectively the same, with the Guide bushing being replaceable with the brass one only in the ATE

#13

Just since we are talking about rules (and I love to argue;)

Technically you cant swap ATEs/Girlings unless you also swap the master cyl & proportioning valve. From what I can tell those two parts are specific to the caliper type. If allowed to swap, once could mix and match to get a different (and more favorable) F/R bias.

Im new to all this, so I know I don’t have as much sway. I would think that the brake pin guide bushings are illegal (and should stay that way). The rules don’t allow them. Is the taper wear of the pads so bad they are necessary? Don’t you replace the pads long before the taper would cause metal to metal contact? If so, they are an unnecessary expense. Spec miata has allowed spec creep to add HUGE costs to building a competitive car. Something I would like to avoid.

Tnx,
SMD

#14

I have the girlings and the pad wear through 4 hpde’s is slightly tapered.

Like someone mentioned earlier, I think at the point of nearing metal to metal contact on the "low" end its time for new pads anyway and won’t really effect overall pad life.

Ryan

#15

The cost is not just $50, the ATE cals are around $300-350 per axle. Looks like $400 is in the ball park for the ATE cals. I’m not aware that you can get the brass bushs for the girlings!!

I got lucky on ebay last week and got a set of front ATE cals for $40 shipped. If your patient a good deal on ate cals is possible. I’m you want them now your gonna pay

#16

bmwbadboy wrote:

New ATE calipers are $125, each, from PacificBMW, shipped… ask me how I know. (It’s the same way that I learned that ft-lbs ≠ in-lbs and that you can’t get a new bleed screw without a new caliper.) :blush:

#17

Sure you can get a new bleed screw. Its a M7x1.0 - same as most VWs (and other european cars w/ small brakes) and probably $1 at autozone. Autozone also list rebuilt calipers for $90 (incl core) but I can’t tell if they are ATE or girling…

SMD

#18

Well, thanks for that info, I’ll keep that in mind – unfortunately, the screw snapped off in the bleed hole and was in so tightly that it actually destroyed a heavy-duty Craftsman drill-out bit in the fruitless attempt to get it out. (It’s what I get for rushing and mis-reading the torque specs – and for not using common sense that 27 ft-lbs is a bit much for such a small part).

#19

Car Quest charged me $2.85 for a bleed screw!!

#20

You should get speed bleeders then.

Also rebuild kits for ATE’s harder to get. They aren’t stocked everywhere like the Girlings are.