Hello all...I am working on a 1959 Chevy NAPCO 3100 project. When I bought the truck it had no front brakes or front wheel cylinders. I have since learned that I am looking for 1949-1955 Studebaker 2R5, 6, 7 truck brakes with self-adjusters. I have found a source for the Studebaker parts however I am struggling with the brake wheel cylinders. No one seems to know what NAPCO used and I cannot find a used set anywhere that I could send in for rebuild....and I don't even know what they look like! I cannot believe that they would be made exclusively for the NAPCO and wonder if the Studebaker 2R5 wheel cylinders would have been used along with the backing plates. Any help would be appreciated. Thanks so much. -Steve-
1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)
On my 1957 GMC 1/2 ton Napco, they are "stepped" wheel cylinders on the front (2 different sized cylinders). When I rebuilt them, I had to source the wheel cylinder rebuild kit from a Studebaker website (I don't recall which one).
Jim Carter Truck Parts has some for 55-57 Napco Trucks. Part # NA125L and NA125R. You can see them on their website for reference or call 800-842-1913.
1957 GMC 100 * Line Built Napco * Pontiac 347 * 89" Stepside * Purchased new by Grandfather from my Father's dealership in 1957. 1967 Camaro RS Convertible 1968 AMC Rebel 1966 Ford F100 Crown Vic swap 1968 Mercury Cougar Barn Find
Following up with GrandpasJimmy, I looked up the parts info for 55&57 GMC 1/2 ton with "driving front axle" and found the drawing below in the 55.2-60 GMC Master Parts Book. I know this is GMC info and you are asking about Chevies, but MAYBE they are the same????
The slave cylinder does look like it is different sizes on front and rear in the drawing. I can get GM part numbers for any of these parts and maybe one of the part number gurus can find the parts.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
Thanks for the quick response....I will shoot Jim Carters a call...I emailed them months ago asking if the 55-57 NAPCO wheel cylinders would work in a 59 and they did not respond to my inquiry ..... Otto, you are correct in that I have no wheel cylinders, I was lucky enough that I had the brake pads on the left front but had to find a set for the right front. They are not available outright because they are so rare. You have to send yours in to the Studebaker parts dealer in order to get a pair that has been re-lined. I had posted a question on the Studebaker Drivers web site and one of the members sent me a pair of shoes for the cost of shipping (my hero) so I do have two pair to send in for exchange. I appreciate the tip about Brake Materials & Parts Inc. Some years back a Youtuber (Jeff Maxwell of Elderly Iron) posted a video showing him doing a front brake install on a NAPCO he was restoring and he used Dorman wheel cylinders and had special front brake lines with banjo fittings made by the folks at Pacific Rubber Products of Eugene, Oregon. It is a video worth watching as are all of his videos...he is unfortunately no longer with us but clearly was a great guy with loads of talent and a great sense of humor! Here is a link if you are interested. Napco Studebaker Brake Installation Crusty Old Grand Dad 1957 Chevy 4x4 Truck
Thanks -Steve-
Last edited by Gdads51; 10/22/20262:38 PM. Reason: fix video link to not embed in server
This is GMC info for what they call a FH030 driving front axle on a 1/2 ton chassis. I don't know if the Chevy parts are the same.
RH wheel brake cylinder. 1958-9 GM part number 3741926 LH wheel brake cylinder. 1958-9 GM part number 3741925 RH wheel brake cylinder. 1956-7 GM part number 2352833 LH wheel brake cylinder. 1956-7 GM part number 2352834
I found THIS looking for 3741926, but the picture doesn't look right. Then I looked up the Dorman's W41718 that this page referenced. Again the picture looked wrong and it did not mention the Chevy or GMC 4wd trucks.
I had no luck searching for the other 3 numbers.
Additional info from the GMC parts book shows that each 56-57 4wd front wheel cylinder used 2 different sized pistons, while the pistons in the 58-59 wheel cylinders used 2 of the same pistons.
Last edited by Bill Hanlon; 10/22/20263:12 PM.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
Bill's first two numbers do not show up on any gmpartswiki search.
The second two show up in the GMC September 1963 Master Parts Book X-164001 The 2352833 also shows up on a 1979 supersession book as Removed.
Searches didn't show any of those 4 numbers in any Chevy parts books.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
Based on Bill's research, I did some diving through through both GMC and Chevy Master Parts Books and the web. Both Chevy and GMC list the same front wheel brake cylinders for the 3100 1/2 ton 4 wheel drive front axle for 1958-59 as Bill indicates (note part numbers have some transposed numbers). Chevy actually lists them as 1957-59.
The descriptions of those pieces show they are one inner diameter - 1-1/16" on both ends, and not the stepped two different diameter wheel cylinders used in the earlier forward drive axle assemblies.
More diving through the parts books show that GM#'s 3749126 and 3749125 are listed as sourced from BP (Bendix Products) Part Numbers 49455 and 49454 respectively.
I checked an old NAPA Brake Parts catalog to see what it listed, but only found it listing wheel cylinder repair or overhaul kits, NAPA#s "20" and "20H respectively. Those kits confirm that the cylinders do use a single 1-1/16" bore to match the GM data.
Using the original part numbers and Bendix numbers, I searched a parts history listing for US Gov parts and came up with the following cross referenced manufacturers and part numbers that it list as replacements for the original GM part numbers (these are specific to GM# 3749126 only) :
Both of these are relatively inexpensive and you should be able to acquire and test fit to be sure they will work on your backing plates.
Best of luck Steveoreno, and please update on findings/results!
* Edit Note = Corrected my part number typo from w47719 to W41719
Last edited by Gdads51; 10/23/20261:58 AM. Reason: correct part nmber typo
~ Dan 1951 Chevy 3 window 3100 Follow this story in the DITY Gallery "My Grandpa Carl's Truck and How it Became Mine" 1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver) US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)
Wow! You guys are amazing!! I am going to order the Dormans from Amazon and see how they work although I am not ready for them yet I can at least mock things up! Gdad ..is the Dorman part number for the RH front W41719 and not W47719? I couldn't find the W47719 on-line but the W41719 is available. Thanks to you all...this has been a mystery! -Steve-
Steveoreno - Good catch! My stubby fingers failed me again - hahaha.
I corrected the typo so it doesn't lead anyone else astray.
~ Dan 1951 Chevy 3 window 3100 Follow this story in the DITY Gallery "My Grandpa Carl's Truck and How it Became Mine" 1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver) US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)
LOL...I do that all the time as well. I did a part interchange inquiry after reading so many negative reviews of the Dorman products and ended up going with Raybestos WC9091 and WC9090 wheel cylinders. I will post the results once I give them a test fit. Right now the entire front diff is out of the truck....actually the only thing bolted to the frame is the empty cab....and it is getting ready to come off and onto my cab cart. I should be able to approximate though. Thanks again...I am so impressed and so thankful by the results of my inquiry ! -Steve-
