ElectraVan 600 Brakes Upgrade
Robert MacConnell <firstname.lastname@example.org> <robmac1958@GMAIL.COM>, Richmond, Calif.
The following is a restatement/condensation/annotation of a series of posts by Mr. MacConnell to the EV600-L listserve, mainly in 2006, plus later private email updates that supply details. The topic is upgrading the OEM brakes on the Jet Industries EV600 ElectraVan, a vehicle based upon the Subaru 360 Van (AKA "Sambar" in countries outside the USA). The Subaru 360 Van is equipped with 10" wheels. The Jet Industries conversion to electric power entails a substantial increase in weight, for which the Subaru OEM brakes are woefully inadequate.
Summary of modifications:
- '88 Subaru Justy 12" wheels
- machine center hole larger to fit Austin/Midget front hubs
- Datsun master cylinder, 1967 1/2 through 1970 Datsun 1600/2000
roadster, no proportioning valve
- Dorman #610-404 wheel studs (which were ~5mm too long)
- Fabricated mounting bracket
- Front hubs: '66-79 Austin Healey Sprite/MG Midget.
- Original van front wheel bearings
- Grease seal from the rear wheel of a 2wd Subaru Justy.
- Caliper brackets: Nissan Sentra -- modified (note: try using the whole Justy caliper and bracket assembly and fabricate your adapters accordingly)
- Calipers: '88 Subaru Justy front
- Rotors: VW Golf vented (need donor application year), turned down from 240mm to 227mm OD
- '87-88 Subaru Justy 2WD front hubs w/24-spline flanges. Axle dia. and spline count matches the 600.
- knock out the existing wheel studs and drive in longer ones. I used Dorman part# 610-404 .;
- Transfer old rear drum grease seal collars to Justy hubs.
- '88 Honda Civic rear brake assy (backing, drum, e-brake cables.)
- Backing plate mounting modified for larger center hole, relocate outboard the four mounting stud holes
- e-brake cables shortened.
- e-brake cross bar clearanced to to clear axle flange
- Original axle housing clearanced at flange OD to clear e-brake cross bar
----------------- SYSTEM ---------------
The master cyl is for a 1967 1/2 through 1970 Datsun 1600/2000 roadster. I purchased mine new from http://www.sportsimports.ca Part# 4600117. It uses 3/8-24 thread fittings. The brake lines on the ElectraVan are 10mmx1.0. I purchased adapters from NAPA auto parts. I can't find a part# for them but they were readily available.
The plastic reservoirs for brake fluid were discarded and the van "underdash" reservoir was retained. The reservoir hoses were attached to the Datsun master cylinder using plastic "tops" from a '79 Mitsubishi truck master cylinder. No proportioning valve was used. It would likely be needed if some type of power booster was installed. No attempt made thus far.
[click on any image for larger]
----------------- FRONT ---------------
Modifications made to the MG wheel hub: MG used a ball bearing system while the ElectraVan uses tapered roller system. All of the ball bearing equipment (including the races being driven out) was discarded. All you want is the bare hub casting!
There were no modifications made to the outer bearing side at all. All of the machining is done on the inner bearing side. Essentially you are attempting to do two things. first, shorten the distance between the bearings by 11mm. Second, machine the MG hub to accept the ElectraVan inner bearing race and grease seal.
I brought the MG hubs and the ElectraVan front brake drum assemblies down to my machinist and VERY CAREFULLY explained to him what I was attempting to do. Fortunately he was a smart guy and did it just right.
The MG uses a 4 on 4" wheel pattern with these tiny skinny wheel studs. The Subaru Justy uses a 4 on 100mm wheel pattern with 12mm 1.25 stud. The stud holes were cut on a milling machine. They were simply bored right over the original holes. It worked out because of the increased diameter.
Notes on the Sentra caliper brackets:
My "original" design used solid MG front rotors which proved to be an immediate failure because the MG rotors were too small and overheated badly. The Sentra brackets were used in conjunction with the MG rotor setup because the Sentra uses a solid rotor like the MG *and* uses identical caliper and pads as the Subaru Justy which uses a vented rotor.
My "second generation" design incorporated the vented VW Golf rotors in
order to relieve the overheating problem, which it has quite well. For someone starting from scratch, you just use the whole Justy caliper and bracket assembly and fabricate your adapters accordingly. Forget you ever heard of a Nissan Sentra. I only used them because I had previously drilled my adapters to fit them. No need to repeat my mistakes!
----------------- REAR ---------------
'88 Honda Civic rear brakes on the back of my van with the help of some Subaru Justy parts.
Part 1: Fitting the Honda backing plate to the ElectraVan swing arm.
A '88 Honda Civic DX provided its rear brake drums, backing plates, shoes, wheel cylinders, all springs & hardware and e-brake cables.
- Remove from your van: Rear drum, E-brake cable & sheath, disconnect brake line, unbolt & remove backing plate assembly.
- Completely disassemble your Honda brakes so you are left with the bare backing plate. The modification will consist of enlarging the center hole and moving the four bolt holes outward to match the ElectraVan dimensions. First is enlarging the center hole from 62mm to 78mm. I made a template out of a piece of sheet metal with the exact van layout and scribed it onto the Honda plate. Make sure that it is centered precicely. I used a saber saw with a medium metal cutting blade. Slow & easy makes a nice clean cut. I left a small amount of material so I could hand file a perfect fit. You want the plate to fit snug with no looseness. Don't worry that the new center hole has cut into the 4 original bolt holes.
- Cut out the 4 new bolt holes. Get 4 flat washers 8mm inside hole, min. 17mm outside diameter and at least as thick as the backing plate metal. Mount the Honda plate on the van swing arm with the washers between the bolt heads and the backing plate. Now weld the washers on to the backing plate. This gives you nice clean bolt holes and double thickness of metal. The final step is to weld up the voids left by the original bolt holes and clean up with a grinder. Paint and bolt on your new backing plate.
- The outside diameter of the hub flange needs to be ground down a few mm's to allow the Honda drum to seat fully when installed.
First, permanently install the modified backing plates and mount the wheel cylinders. Note: the van brake line fittings match the Honda wheel cyls. Mock up the shoes and adjusting hardware. You'll notice interference between the Honda adjusting strut and the top of the wheel bearing housing. I remedied this by grinding some metal off the top of the bearing housing and a corresponding flat on the bottom of the adjusting strut. This yields 3-4mm clearance upon assembly. On to the E-brake cables. The plan is to cut down the Honda sheathings to match the van sheathings, using the same mounting place. Then clamp the two cables together. For reference I will call the end of the cable at the brake, the brake end and the other end at the hand lever will be the lever end. First, cut the lug off the lever end , pull the cable out of the sheath and set aside. Next clamp the metal part, at the lever end of the sheath, in a vise and pull the sheathing off. It's pretty easy. Mount the part (from the vise) onto the van swing arm using the van hardware.
Cut the sheath so the length is correct allowing for suspension travel. Note: The sheath is hardened steel. It must be cut with a grinder. A saw won't cut it. Mount your modified sheath to the backing plate and attach the cut end to the metal part (from the vise) using Loctite. Feed the cables through the sheathings. This is a good time to complete the assembly of the shoes & adjusting hardware. To finish the E-brake, take the cables and feed them through the crescent shaped part (CSP) mounted on the rod which runs down the center of the van. One cable from each side. Note: Tight fit. Now clamp the cables using hardware store cable clamps. I used EIGHT of them. You don't want these slipping!
Part 3: Mounting the Subaru Justy 2WD front (yes, front) wheel hub to the van rear axle.
Donor hubs were from '88 Subaru Justy 2WD. It provided its front wheel hubs, wheels & tires.
This is the single part which really makes this swap possible. The Justy hubs have the same diameter axle and spline count as the ElectraVan. The Justy hub also has a 4 x 100mm stud pattern which allows mounting the Honda brake drum as well as "normal" wheels & tires.
Since doing the conversion, I have learned that these Justy front hub/flanges come in two sizes. They are a 24-spline size and a 27-spline size. It's critical to get the 24-spline size because the ElectraVan has 24-spline axles. I believe that the 24-spline hubs were only used on the '87 & '88 2wd Justys. I'm not 100% sure of this.
Two things need to be done to the hubs prior to installation.
- First, knock out the existing wheel studs and drive in longer ones. I used Dorman part# 610-404 . These actually proved to be about 5 mm too long. I had to trim them to get my wheel covers on. Perhaps there is a better size?
- Second, there is a small steel collar pressed into the ElectraVan rear brake drum. This part provides a surface for the rear axle bearing grease seal to ride on. This needs to be VERY CAREFULLY removed and installed on the corresponding boss on the Justy flange. The Justy hub's boss is slightly smaller in diameter. I made up the gap by making a shim out of sheet shim stock (I think I used .020") and installing it with Loctite. The installed height of this collar is critical as the axle grease seal rides on it. Match the height originally installed on the van drum.
Bolt on the Justy hubs using the van's cone washer and nut. Torque axle nut to spec. (have to look it up). Install the drum, adjust the shoes, bleed the hydraulics, adjust the E-brake , bolt on your wheels & tires.
I recommend an initial test drive to be done on level ground and sparse traffic. Upon completion of mine I completely disassembled it and checked everything out. So far no problems! The braking feel is no different but the motor RPMs are lower due to the larger tire diameter. In closing I'll say I have new found respect for technical writers. If I failed to describe anything adequately, please let me know and I'll try again.
Author's notes as of 14Dec2007
I've been driving the van with its new brakes for over a year now and I am very satisfied with the setup. If I was doing it over again there are two things I might do differently:
First, I would seriously consider mounting the master cylinder on the chassis under the floor similar to the way it was done on the 60's Dodge A100 vans. This would allow room to install a power booster.
Second, I would take a long hard look at using 13" wheels (instead of the 12"ers) with a very low profile tires. The diameter of the tire at the tread is the critical clearance issue. The rim size doesn't matter so much. I will say that it was a huge challenge to get all that disc brake equipment to fit behind a 12" wheel. The 13" rims would also allow larger drums on the rear.