c3 disc brake pad questions

[Robert E.]

Re: c3 disc brake pad questions

Thanks guys

Rob

[Joe L.]

Re: c3 disc brake pad questions

Joe, I just got off the phone with my local GM dealer to enquire on the price of GM #18028641 pads. At $70 and still available, he questioned it's application (front or rear). I suggested they were more than likely the same, but he didn't agree.

Please assure me that the pads mentioned apply to all four corners.

Thanks in advance

Robert

Robert------


Terry already answered it but I'll also confirm that the front and rear pads are exactly the same for 1965-82 Corvettes with one exception. That exception is those 1967-75 Corvettes equipped with J-56 brakes. Those pads were different front and rear and also different from those used on non-J-56 cars. The counterman does not have to worry about those, though, since they are long-since GM discontinued and replacements available only through specialty brake parts suppliers.

[Jim T.]

Re: c3 disc brake pad questions

Not to take away from your purchase of the GM brake pads, however I last used Bendix D8's by Honeywell Made in USA brake pads. Bought them at my local part store that sells AC Delco parts. The box says O.E. Formulated. Wonder if GM uses this supplier for their brake pads?

[Timothy B.]

Re: c3 disc brake pad questions

Here are pictures of the disc pad set I purchased at Carlisle. I was hoping someone could tell something about these pads. They came in a unmarked box and from the same person that sold me the #546 (1965-early 67) brake calipers.

What does the code mean that's rolled/painted on the top of the pad, looks like USA-AT-FE and the USA is upside down and hard to read.. The metal backing say's made in Canada..

[John H.]

Re: c3 disc brake pad questions

What does the code mean that's rolled/painted on the top of the pad, looks like USA-AT-FE and the USA is upside down and hard to read..

Tim -

Dunno about the "AT", but the "FE" is a DOT-required marking that describes the pad's coefficient of friction at 250*F and 600*F, and fade resistance/temperature profile. "EE" is the lowest, then "FE", "FF", "GG", and "HH". The "GG" marking is for all-out race pads, and "HH" is for carbon/carbon.

[Timothy B.]

Re: c3 disc brake pad questions

Thanks John,

Hopefully others will respond with more information because I would like to use them on my 67. I am curious if these are the GM pad #18028641, I will try to search the ratings on the 8641 pad.

[Timothy B.]

Re: c3 disc brake pad questions

Joe, I just got off the phone with my local GM dealer to enquire on the price of GM #18028641 pads. At $70 and still available, he questioned it's application (front or rear). I suggested they were more than likely the same, but he didn't agree.

Please assure me that the pads mentioned apply to all four corners.

Thanks in advance

Robert

Robert,

After reading what John Hinckley posted about the coefficient of friction, the difference between front and rear pads may be that rating. For example front pads may work better with a FF rating and rear with FE rating. This would mean the rear pad would be better at the lower temperature and fade some at higher temps where the front pad is good at the 250* cooler temperature and also good at the higher 600* temperature, a good street front pad and a good compromise in the rear because the front does most of the braking.

If I'm correct the higher the coefficient rating the better the bite but dust and noise becomes a factor.

This is a good topic for discussion as many would benefit from this knowledge.

[Joe L.]

Re: c3 disc brake pad questions

Robert,

After reading what John Hinckley posted about the coefficient of friction, the difference between front and rear pads may be that rating. For example front pads may work better with a FF rating and rear with FE rating. This would mean the rear pad would be better at the lower temperature and fade some at higher temps where the front pad is good at the 250* cooler temperature and also good at the higher 600* temperature, a good street front pad and a good compromise in the rear because the front does most of the braking.

If I'm correct the higher the coefficient rating the better the bite but dust and noise becomes a factor.

This is a good topic for discussion as many would benefit from this knowledge.

Tim------


It may be that differently rated pads would, by some measure or opinion, work better for the front and rear. However, GM never thought so (at least for non J-56) and used in PRODUCTION and specified for SERVICE the same pads, front and rear.

[Steven B.]

Re: c3 disc brake pad questions

A couple of things on pads based upon my experience working for a brake and clutch manufacturer as a prod. mgr.;

The Friction Code is required by the Govt. refer to SAE Standard J866a. Other edge stamp codes are specific to the manufacturer identifying Brand and Quality Codes and internally generated. Sometimes the jobber or parts dept. can interpret but most often only the manufacturer will know. As an example where I worked we manufactured semi and large truck brake blocks identified by ST and TG, ST for Silver Tip and TG for True Guard. We had similiar coding for cars. Othe rmanufacturers used totally different codes for same compounds. The internal Quality identifier is often equivalent to the Coefficient of Friction and materials. The Friction Codes are in accordance with SAE J661 and determined by using a Chase machine. A square of the friction material is pushed against a rotating drum generating a BASE LINE result, not necessarily real world experience.

The Normal (Cold) Friction Coefficient, the first letter of the 2 letter code, is the average of 4 points on the 2nd Fade Curve, at temperature points of 200F, 250F, 300F, and 400F. The Hot Friction Coefficient, the second letter, is the average of 10 points on the first recovery of 400F and 300F and 450F, 500F, 550F, 600F, and 650F on the second fade, and 500F, 400F, and 300F on the second recovery.

Friction materials are comprised of Fibers, Fillers, Friction Modifiers (they fine tune the Coefficient of Friction), and Resin Binders. (Once we experimented with cashew nut oil in a resin binder. It was better than anything we used to date but was prohibited due to cost.) Lining types fall under the following: Low Metallic, Non Asbestos Organic, Ceramic, Semi-Metallic, Sintered Metallic (iron), and Carbon. Backing plates and the friction material are either riveted, bonded, or molded bonded.

At times different manufacturers would supplement GM/Delco friction products quantity requirements. Some of these manufacturers were Raybestos, Wagner, bendix, and Maremont (Grizzly). Some supplied other manufacturers who in turn supplied GM. Packaging in these instances usually were plain white boxes or GM/Delco packaging and sometimes packaged as an axle set or in bulk.


Although some internal testing has been done by manufacturers as to different Coefficients of Friction for front and back usually are sold as the same for front and back. This is done for liability reasons, the unknown of the use for the pads and driving style/capability, and possibility of unequal braking and control, pull, and uneven wear.


Steve

[Domenic T.]

Re: c3 disc brake pad questions

A couple of things on pads based upon my experience working for a brake and clutch manufacturer as a prod. mgr.;

The Friction Code is required by the Govt. refer to SAE Standard J866a. Other edge stamp codes are specific to the manufacturer identifying Brand and Quality Codes and internally generated. Sometimes the jobber or parts dept. can interpret but most often only the manufacturer will know. As an example where I worked we manufactured semi and large truck brake blocks identified by ST and TG, ST for Silver Tip and TG for True Guard. We had similiar coding for cars. Othe rmanufacturers used totally different codes for same compounds. The internal Quality identifier is often equivalent to the Coefficient of Friction and materials. The Friction Codes are in accordance with SAE J661 and determined by using a Chase machine. A square of the friction material is pushed against a rotating drum generating a BASE LINE result, not necessarily real world experience.

The Normal (Cold) Friction Coefficient, the first letter of the 2 letter code, is the average of 4 points on the 2nd Fade Curve, at temperature points of 200F, 250F, 300F, and 400F. The Hot Friction Coefficient, the second letter, is the average of 10 points on the first recovery of 400F and 300F and 450F, 500F, 550F, 600F, and 650F on the second fade, and 500F, 400F, and 300F on the second recovery.

Friction materials are comprised of Fibers, Fillers, Friction Modifiers (they fine tune the Coefficient of Friction), and Resin Binders. (Once we experimented with cashew nut oil in a resin binder. It was better than anything we used to date but was prohibited due to cost.) Lining types fall under the following: Low Metallic, Non Asbestos Organic, Ceramic, Semi-Metallic, Sintered Metallic (iron), and Carbon. Backing plates and the friction material are either riveted, bonded, or molded bonded.

At times different manufacturers would supplement GM/Delco friction products quantity requirements. Some of these manufacturers were Raybestos, Wagner, bendix, and Maremont (Grizzly). Some supplied other manufacturers who in turn supplied GM. Packaging in these instances usually were plain white boxes or GM/Delco packaging and sometimes packaged as an axle set or in bulk.


Although some internal testing has been done by manufacturers as to different Coefficients of Friction for front and back usually are sold as the same for front and back. This is done for liability reasons, the unknown of the use for the pads and driving style/capability, and possibility of unequal braking and control, pull, and uneven wear.


Steve

Thanks Steve,
Now that confirms what John H said.

Just use the generic pads UNLESS you are going to professionally race the car, generic pads = EASY on the rotors.

Replace pads, or pads & roters if you use the metalic pads.

DOM

[Michael W.]

Re: c3 disc brake pad questions

Thanks John,

Hopefully others will respond with more information because I would like to use them on my 67. I am curious if these are the GM pad #18028641, I will try to search the ratings on the 8641 pad.

There's all sorts of aftermarkets pads available for C2/C3 cars. Finding out who made the pads in question will most likely be a futile exercise unless a part number or manufacturer's name is available. Just curious- why would you NOT use these pads?

[Timothy B.]

Re: c3 disc brake pad questions

Steven,

These pads I pictured came in a plain white box as one axle set, (four pads), and handwritten on the box was "66" rear pads. Presently on my 67 are HD brakes and they may be semi metallic that don't stop worth a darn, I don't know what brand so I can't describe further than the receipt from a long time ago.

Michael,

I will probably use them on my car if they are not semi metallic, I just got a education about the friction ratings and with a non power brake car I think this is important to consider.

Can anyone tell me the DOT friction code rating on the currectly available GM pads and if they are ceramic or some organic. My bet is they are rated FF..

[Steven B.]

Re: c3 disc brake pad questions

Tim, sorry I can't help with the manufacture. My manufacturer and marketing code book was tossed a few years ago because it was a shop copy I used and full of asbestos. My remaining books don't have that info., unfortunately. Since yours were likely packaged in the plain white box they were made to be resold not under the manufacturer's name.

Steve

[John H.]

Re: c3 disc brake pad questions

Steven,

These pads I pictured came in a plain white box as one axle set, (four pads), and handwritten on the box was "66" rear pads. Presently on my 67 are HD brakes and they may be semi metallic that don't stop worth a darn, I don't know what brand so I can't describe further than the receipt from a long time ago.

Michael,

I will probably use them on my car if they are not semi metallic, I just got a education about the friction ratings and with a non power brake car I think this is important to consider.

Can anyone tell me the DOT friction code rating on the currectly available GM pads and if they are ceramic or some organic. My bet is they are rated FF..

Tim -

I have two new-in-the-box axle sets of AC-Delco "DuraStop" pads, Delco #17D8, GM #18028641 (list $42.00 per axle set) waiting for our next swap meet that someone sent me; they appear to be semi-metallic, and are "FF" rated. They look just like the set I removed from my manual-brake '67 right after I bought it twelve years ago; pedal pressure was very high vs. expected normal stopping power. I replaced them with a $20.00 per axle set of OEM-type organic pads from Paragon, and they instantly solved the pedal pressure issue; they'd probably work fine on a power brake car.

[Joe L.]

Re: c3 disc brake pad questions

Tim -

I have two new-in-the-box axle sets of AC-Delco "DuraStop" pads, Delco #17D8, GM #18028641 (list $42.00 per axle set) waiting for our next swap meet that someone sent me; they appear to be semi-metallic, and are "FF" rated. They look just like the set I removed from my manual-brake '67 right after I bought it twelve years ago; pedal pressure was very high vs. expected normal stopping power. I replaced them with a $20.00 per axle set of OEM-type organic pads from Paragon, and they instantly solved the pedal pressure issue; they'd probably work fine on a power brake car.

John------


If the GM #18028641 are semi-metallic that would surprise me. The 18028641 are direct replacements for GM #1154122 which are non-metallic and trace their "lineage" all the way back to GM #2621609 and 5452513 which are also non-metallic. These pads were used in PRODUCTION.