Alpine Rear Disc Brakes

Much has been said about the Alpine and the Tiger braking system and the lack of adequate stopping power over the years. As we travel onto the interstate highway system and more heavily trafficked roads with our cherished Sunbeams, “enhanced braking” becomes more desirable.

My good Friend Bill did a rear disc conversion years ago to his FORD powered Sunbeam Alpine. When I became aware of his rear disc brakes, I asked how it was accomplished. Bill has provided me with some very valuable info that I wish to make available to other Sunbeam Owners.

As usual, I started cutting templates out of cereal boxes, then handed them off to my Draftsman/Engineer Buddy who made drawings and laser cuts for a set of brackets and spacers that will bolt to the rear axle flanges of our Sunbeams. After several attempts to get the angles, spacing and bolt holes properly dimensioned, they were finalized and installation on my Blue Boy V6 was accomplished. I have never had such good braking on my Sunbeams.

The calipers from the rear of the 1992 Saturn SC bolt snuggly to my newly designed “kit” bracket. The mixture of Standard and Metric bolts is common practice when adopting new stuff to the old vehicles like we do when Converting a FORD (Cologne) V6 to the Alpine. The Cologne is Metric and the Alpine is British which requires a lot of “Attention to detail”!

Each rear wheel gets the “new” designed bracket bolted to the Sunbeam rear axle flange using three 5/16-24 grade 8 bolts, nuts and washers (lengths depend on spacers used) then the Saturn caliper bracket gets fastened to my “kit” bracket by two (2) Metric 10mm 1.5 20mm bolts 10.9.

Hub removal may be necessary in some applications for the stock 4 bolt hub as pictured below. Stock wire wheel hubs need to have some machine work accomplished to true the hub for fitting of the rotor on the rear (backside) of the hub.

Neither the Saturn rotor bolt pattern nor the center hub opening will align with the Sunbeam. The Saturn rotors will require some machine work drilling new lug bolt holes and enlarging the center of the Saturn rotor to match the hub. All easily accomplished by a good machine shop. Remember the center of the rotor serves as a guide/pilot for truing the rotor. Suggest you utilize your stock rear drum to use as a pattern to machine the rotor. No guess work that way.

In the next picture the rotor is mounted on the reverse side of the hub. This is a must do for fitting the Saturn caliper on the rear for wire wheel applications.

When the rotors are to be mounted on the rear/backside of the hub, you can reuse your 7/16 – 20 ¾” length bolts, however, new grade 8 bolts w/replacement star washers and additional length of ¼” is recommended.

Below is the rotor after machine work is done cutting the new four bolt holes and the center enlarged to match the guide on the hub for the front/outside mounting of the rotors.

And here is info on the Saturn Calipers recommended for mounting on the Sunbeam Alpine/TIger. Rear right hand side (Passenger in US) Caliper Number 18-B4524

Rear left hand (Driver in USA) side caliper number 18-B4525

Here is the info on the Brake Hoses I purchase for the Saturn calipers:

ApplicationManufacturerPart #DescriptionPrice EachQty Needed
1992 SATURN SC COUPE 1.9L L4CENTRIC15062355 (150.62355)Hydraulic Hose$8.482

The above picture provides the GCX Part number 320.62037 for the rotor.

Notice picture above…. It is for the wire wheel with a rotor mounted on the back side of the hub. Normal spacing I have found for the wire wheels is four ¼” spacers and perhaps one other thinner spacer to get proper alignment. The wire wheel kit will have eight ¼”, two ⅛” and two 1/16” spacers as standard. Additional spacers are available if required. A special note of attention is the spacers utilized to adjust the caliper do not cause the wheel to be moved any further than stock position. Prior wheel to fender clearance on my Alpine with the rear calipers are the same.

The Saturn caliper pictured above has two 10mm1.5 threaded holes where it is mounted to the “Kit” axle housing bracket.

The below PIC is the Kit bracket, with a ¼” spacer and some various bolts for mounting the rear Calipers to the Sunbeam rear axle flanges. The black bolts are 10 mm 1.5 x 20 mm long for connecting the caliper bracket to the Kit mount bracket which fastens to the axle flange. The other bolts, nuts and washers are for connecting the Kit bracket to the axle flange. These bolts (grade 8) will vary in length based upon the number of spacers needed for alignment of the rotor and caliper. Kit spacers are ¼”, ⅛” and 1/16” thick.

Pictured below are a couple Kit brackets with some ⅛” and 1/16” spacers & the E-brake levers. Brackets and spacers will come powder coated.

The below picture is the Saturn E-brake spring return and lever. The Saturn return spring must be removed, then the nut holding the lever.

NOTE: Do Not Let The Lever Move/Turn!! It must be held steady so that the caliper piston does not engage. If the piston engages, it can extend beyond the point it can retract.

The following picture shows the Kit E-Brake lever and the position to install.

The levers are designed to fit specifically right or left. They are to be installed with the slotted finger up to “catch” the return spring.

Suggest you have all of the components required on hand before you start pulling your Sunbeam apart, Just to be able to see what you will need and how it “fits” together.

As an example, in what condition is your stock Sunbeam hand brake cable and the adjustment ends? Can you remove or adjust the length of the end where the cable yoke and nuts are utilized to adjust the hand lever for parking/braking ?

I broke the E-brake ends on two of my Alpines (stored for years) just trying to adjust the brakes, they had rusted beyond repair even with WD-40 soaking for a long period. I purchased a new one! They are available from Classic Sunbeam (NY) and Sunbeam Specialties (Calif).

I had the “wire” shortened about 2 1/4 inches by a Local Airport guy. He wrapped the wire/cable with tape to keep it from fraying, cut the wire/ cable where I had marked the end with “blue”, then swagged the end for me.

Your length requirements may vary from mine! My dual exhaust on Blue Boy hampered a straight pull. So, your cable may be shorter than my 2 to 2 ¼”….

You should measure yours before cutting to ensure adequate length allowing for future adjustments.

Note In the PIC below: See the “blue” mark on the wire cable ? Here is where the Airport Shop Guy wrapped the tape to cut the end off.

Part Numbers and other data as applicable

Brake Line T-Fitting 3/8″-24 Inverted Flare Run Part Number: 361-972050 · 3/8″-24 Inverted Flare · 3/8-24 Straight on BranchRun · Mounting Hole: 1/4″ Approximate cost: $14.00 to $50.00, Just shop around.

Below are pictures of the fittings used to connect the Saturn caliper (metric) to the Sunbeam rear brake system.

Pictured below is a “Straight” run that the Sunbeam brake hose screws into. There are two inverted flare positions, one for each of the Saturn hoses (metric) to be fed. In the picture below the “hole” is where the stock Sunbeam brake hose is fitted. It serves as the feeder thru the tee for the two lines out to the calipers

Next PIC shows one of the inverted flare positions that feed the Saturn hoses to each caliper. The fitting (Tee) shown above and below is a GM-⅜ female. The manufacturer part number is Eaton 326. Suggest you shop around for a better buy cost wise. They can vary from $14 to $50. Earl’s part number is 972050ERL

One connection in the Tee will take the stock Alpine brake hose connected to the hard line from the Master Brake Cylinder. See the below picture (gm-⅜ female).

Below is the Saturn hose (metric) to the Tee. Also seen is the Sunbeam hose routing from the Master Cylinder.

Here are two brake lines with Part Number 6320ST 3/16” x 20” Metric thread Bubble flares I purchased to complete running the rear brake system from the Saturn hose to the Tee from both calipers.

I cut one of the 20” lines to make the short connection (2 ½ to 3”) between the right rear caliper and the “Tee” using the 3/16 metric male fitting and bubble end into the Saturn metric hose female end and a ⅜” -24 male fitting into the flared tee (See below PIC).

Below are two pictures of an Alpine rear axle assembly with a Saturn Caliper & rotor mounted with a Kit bracket, included in the picture are the hoses, fittings and hard lines. The Saturn brake hose running from the caliper has a metric female end. A 3/16 male metric thread bubble flare fitting and a male ⅜-24 fitting on a short hard line was made to screwinto the recommended “tee” with two flared ends. (See below).

A clear view of the Return spring “hooked” in the Kit E-Brake lever.

Also the Emergency Brake Lever is in its position. Notice that this is the right rear side where the “Emergency brake cable” fastens to the E-brake lever. The E-brake rod fastens to the left side. Both function the same as before in the stock location.

The above PIC shows the need of spacing between the Caliper and the rotor…. Perhaps 1/16” or ⅛” spacers will be sufficient. I need to tighten the axle nut and secure the hub before knowing for sure any additional spacing is required.

Here are some wheels I have tested briefly that will work with the Saturn Caliper and Rotor.

Eric G’s Lat 9 needs ⅞” wheel spacer

Eric G’s Lat 72 needs 1” wheel spacer

Eric G’s Panasport 14” needs ½” wheel spacer

Ron’s Wheels 15×7” on Blue Boy needs ¼” wheel spacer

Panasport 15×7 works nicely without wheel spacer

Centerline on Green1 fitted with 14×6 to 6 ½” work nicely without wheel spacer

Pinto and Mustang II 13” wheel needs ⅜” to ½” spacer

Stephens Wheels Compomotive 5.50 x 13 Needs ½” to ¾” wheel spacer

Alpine 13” Wire wheel Mount Saturn Rear Disc Brake

The wire wheel pictured below shows more than adequate clearance for the Saturn caliper and rotor.

As you can tell the wire wheels are some old ones I have stashed away but came in handy for helping get the Rear disc to fit.

Wheel spacers, not part of the Kit, are also available, They mount between the wheel and hub for additional spacing as needed. In some cases where the wheel spacers are used a longer wheel stud may be needed.

We can talk a bit to make sure exactly what you want! I can provide most of the various tid-bits of the kit, so you can be satisfied to the fullest.

A couple purchase options are available:

  1. You can purchase:(Preferred method):
    • My Kit with 2 each Axle flange brackets; 2 each ¼” spacers; 2 each ⅛” spacers; 2 each 1/16” spacers and 2 each E-brake levers and
    • You purchase from a vendor the rotors; calipers; pads; 2 brake hoses; Tee; Metric hard lines w/fittings and form the hard lines (running from metric hoses to the tee); get machine work done locally (match Sunbeam drums to rotors); and remove the stock Saturn E-brake levers and install the ones from my Kit.
  2. Or purchase from me:
    • I furnish the rotors (machine work done), calipers (with Kit E-brake levers installed), pads, 2 brake hoses, the Kit consisting of 2 each axle flange brackets; 2 each ¼” spacers; 2 each ⅛” spacers; and 2 each 1/16” spacers. (Spacers required is normally 1 per wheel); 4 each 10mm1.5 -20 bolts for caliper to flange bracket, 6 each 5/16 – 24 grade 8 bolts (length as required) with nuts & washers for flange bracket to the Sunbeam rear axle housing flange.

Note 1: If your application requires the hub to be machined on the reverse (inside) for truing the rotor and creating the pilot/guide it will be your responsibility.

Note 2: I much prefer you purchase the individual components from a vendor as is noted above, saving you time and money in shipping.

I can provide more PIC’s if you wish. Be glad to answer questions.

My Cell is 864-554-0814 Please leave me a message if there is no answer.

E-mail: tiger2dan@gmail.com

Thanks for looking,

DanR