Bob's Studebaker Resource Website

A Treatise on Studebaker Disk Brakes

Wayne Flowers, Albuquerque, NM - July 2012

          Yes, the Avanti brake system was a Bendix designed system with the front disc brake design being an adaptation of a common Dunlop design of that era. The same basic design/size was used on Jaguar XKE Series 1 froont brakes, Ferrari 330 Series 1 front brakes, and Aston Martin DB4 (the James Bond 'Goldfinger' car) rear brakes among others. The front brakes on the Aston was similar in design but used larger wheel cylinders and pads and a slightly larger and thicker rotor.

        The production Avanti's used 2-1/8" cylinders with 2" square pads. The first cylinders used had a label on them that had the Bendix name in script, later the Bendix name was cast into the cylinders. Replacement cylinders from the factory in later years simply had the Dunlop name cast into the cylinders. Girling bought the Dunlop line and seal kits and current cylinders carry Girling part numbers which I believe are given in the link mentioned by Scott.

        Replacement front wheel cylinders are available in either original equipment style cast iron, rebuilt sleeved in stainless, rebuilt sleeved in brass, or all stainless. Some rebuilders prefer to sleeve in brass as that does not require as much of an interference fit to ensure the sleeve does not try to work its way out of the cylinder. Over the years I bought quite a few stainless sleeved cylinders from Northwest Avanti (in Tacoma?) and never had a problem with them. I do not know if they are still in business. offers original, stainless sleeved, and all stainless cylinders on their web site. Hye-Dra-Cyl in Missouri offers both a 2-1/8" and a 2-1/4" wheel cylinder in all-stainless for the Avanti. I do not know if any of the all-stainless cylinders include the retractor pin that is part of the original style cylinder. I have never used the all stainless cylinders, nor had one apart. AFAIR both Hye-Dra-Cyl and Xksjaguar offer stainless bleeder nipples and stainless jumper pipes for the Dunlop cylinders. Xksjaguar also has the seal kits, but those should be available from the Stude vendors also.

        After this many years the master cylinder may be quite pitted, so it would be worthwhile to have that sleeved also.

        For brake pads, really the original Mintex M33 pads are best, or the equivalent Ferodo DS4, good cold bite and decent heat resistance. Both Mintex and Ferodo used to offer racing versions of the pads, but those must be nearly unobtainable by now. The original Mintex pads appear on eBay occasionally. The S702 pad from NAPA was also a good one, but that is not shown in their online catalog any more. Autozone still shows a pad (look under the Jaguar application), but I haven't used it.

        Autozone still lists the 3/4" wheel cylinder kits for the rear brakes, but I notice they only offer the #176 linings for the rear brakes. It's very close, but the #173 is really the correct lining. As far as rear brake drums go, good luck - hopefully yours are within spec, as the originals are virtually unobtainable since Bendix has not made them for decades. The last ones available from the factory were really drums for the '66 flanged axle version (no tapered bubs included) and you had to very carefully re-use your old hub. Again, eBay is your best bet for NOS drums should you need them. Msny of the rare parts like rotors, Mintex pads, Koni shocks, R3/R4 parts, rear drums, etc. do seem to appear on eBay occasionally.

        Reuse the original cylinder and caliper mounting bolts, or use NOS. These were grade 8 bolts with the wheel cylinder bolts being a custom design. I once upon a time found some aerospace bolts in A286 (high strength) stainless that were the right size. However they were 12pt bolts with ground, drilled heads, so you could not use lockwashers and had to safety wire them. About the only place you might find those now is at the Boeing surplus outlet up in the Seattle area.

        Use fresh hoses front and rear, any Stude vendor should have them. Inspect the lines carefully for rust and replace any that are rusted (the rearmost line along the frame and the ones along the rear axle are usually the worst.

        As an aside, AFAIK the major aftermarket vendors such as Wilwood and AP Racing do not offer a big brake kit for the XKE Jag (if so it should work on the Avanti).

        Here is a bit more information on the Stude disc brake setup used on all Stude Avanti's and early Newman-Altman Avanti-II's. This setup was also an option on '63-'64 Hawks and '63-'66 sedans.

        First let me correct a few errors, some minor, one not so! I referred to the disc brake pad as 2" square, and for casual conversation that is close enough. In actual fact the width is really supposed to be 1.875", the height slightly more. Most of the time the pads are slightly over on the width, which makes it difficult to slide them into the caliper when replacing the pads. Use a fine mill file to take about '005-.010" off the width and they will slide in much easier. If changing out the wheel cylinders, be sure to clean the caliper also. In particular, use some Scotch-brite or steel wool to clean any rust and dirt from the semicircular caliper bores in which the piston of the cylinder rides. Also do this on the small flange at the end of those semicircular bores; that flange acts as a stop for the piston and a guide for the pad. A small, fine, mill file also works well on those flange edges for removing any accumulated rust and dirt that might be preventing easy movement of the pad. Do not paint any of those surfaces.

        An update on interchanges for the Stude pad. I shouldn't have given the interchanges quite so late at night without references to hand, as one or two were not quite right, and I can now add some more. First off I should mention that vehicles sold in the US have an FMSI (Friction Materials Standards Institute) number which identifies their shape. However this number has changed some over the years. For example, the original pad in the US was the 717, this was replaced by the 702. What the difference was I do not know, I've never seen a 717 pad. The 717 number was renumbered as the D28, and the 702 was renumbered as the D23. Napa used to sell the Avanti set as the S702, now they offer none. Autozone offers a set for Jaguar that is a D23 (the new number). In this same sequence the larger S703 pad (2-3/8" wide) used on the front of the Aston DB4 is now the D17 (moot point since only NAPA ever offered it, and as the 703).         Now to complicate matters pads from European manufacturers such as Mintex and Ferodo did not use the FMSI designations, thus in their designation the Jaguar XKE (Stude) pad is the DB704 and the larger Aston DB4 pad is the DB705. But in FMSI speak, the 705 is a completely different shape that was used on Triumph TR-3's! To complicate matters further, although not pertinent here, many aftermarket suppliers such as Brembo, Wilwood, and AP Racing do not necessarily bother with FMSI numbers for their specialty brake pads. Oh, and the original Mintex is now Bendix-Mintex, and makes Repco/Axxis/FMP brand pads in Australia, and Mintex is an entirely different company with no relation.......... The upshot of this is that if you get pads that are from an import parts house such as BAP/GEON or on eBay they will likely be stamped as the 704 style, not the 702.

        No other US manufacturer used these Dunlop cylinders and pads, as somebody noted all the other users were overseas. Here is an updated interchange list:

Aston-Martin DB4 '58-'64 (rear)
Austin 110 '61-'65 (front))
BMW 507,3200 '59-'67 (front))
Ferrari 250GT, 275GT, 300GT '59-'66 (rear))
Jaguar XK150, XKE, Mark '59-'68 (front & rear))
Mercedes 300 '61-'64 (front & rear))
MG Twin Cam '58-'61 (front & rear))
Rover 2000 '64-'66 (front & rear))

        Note that this list includes what are arguably three of the most iconic sports cars yet built - BMW 507, Ferrari 250GT, and Jaguar XKE. Fortunately many XKE's were produced so the caliper parts should be available for quite some time; in fact prime examples of an XKE can probably be purchased for under $100K. The 507 is a different story, extremely scarce, an example went at auction this year for pocket change shy of $1M. As far as the 250GT, as they say, if you have to ask......but you better be thinking of 8 digits. So at least as far as their front brakes, the Avanti is in pretty exalted company.

        These days teflon lined, stainless sleeved brake hoses are popular, frequently with an outer plastic covering to keep the stainless from chafing on chassis parts somewhere. However AFAIK no one is producing these in the Avanti sizes. I had some made about 20 years ago, but they were with AN fittings instead of the standard automotive inverted flare. So be sure and use fresh rubber hoses. I have not seen anybody offer the small jumper pipe between the hose and cylinder in stainless, but I may have missed it if somebody does. If those pipes look at all rusty, change them.

        I made an error in discussing the rear brake shoes. The #176 shoes shown on the Autozone site is completely wrong for the Avanti. That shoe is for cars with the standard drum brake. The 7/8" wheel cylinders are wrong also. The Avanti uses 3/4" wheel cylinders and #173 shoes. Now the #53 shoes for Stude trucks are very close, the only difference is in the linings and the tab that fits into the wheel cylinder is slightly wider. Again, a mill file can be used to take a bit of metal from the tab to make it fit. The tab dimension on the #53 shoe is 27/64"

        Front wheel bearings and seals should be available from most any Stude vendor, or auto or bearing supply house. The drum seal that attaches to the backing plate is hopefully still available from Stude vendors, altho it seems to me that at one time the Stude Parts Corp. (successor to the original SASCO) had them on back order. At one point somebody was sellling the rear shoe adjusters made of stainless, but whether you use stainless or OEM adjusters, do put lots of antisieze on the threads. Oh, and Snap-On used to make a long open end wrench specifically for these Bendix adjusters (I'll look up the part number and post it later).

        Speaking of the Studebaker Parts Corp. reminds me of one time when I was there, probably in the late '60's, John Duncan (did I get his name right??) was telling me that the disc and drum problems might do in Avanti Motors since they were almost out of them in the factory, and Bendix wanted a fortune for making more. Well you know how that was solved, they did indeed have Bendix make more discs, but went with flanged axles and smooth drums in the rear.
        The new Avanti II rear brake was basically a Chrysler setup with a servo'd (Duo-Servo) brake shoe design (self energizing both forward and reverse with both shoes) that are notorious for locking the right rear under any sort or panic stop, or stop on a slippery road. The original setup was a non servo style (forward shoe not connected to the trailing shoe) that was self energizing on the forward shoe only in the forward direction, and self energizing on the trailing shoe only in the reverse direction.

Some specs -

Minimum rotor thickness: 0.330")
Maximum drum diameter: 11.060")
Rear shoe size: 11"x2")
Front pad width: 1.875" (typ. 1.880"))
Front pad usable thickess: .416)
Nominal minimum front pad thickness: 0.250")
Pad to disc clearance with brakes cool: nominal .004")