TOYROTAROB

I have a 1994 Toyota SR5 4x4 extra cab pickup and will be installing Downey's rear disc brake kit with cable parking brake over the next month or so. Has anybody else used this kit? I am really impressed by the visual quality of the pieces. The instructions seem adequate but I was thinking I'd document for others to use. I also have NWOR headers that I installed and documented a couple of years ago. Excellent product and great driveability improvement over stock. I also recently added the K&N cold air intake kit. Not so impressed with that for the 280.00 bucks! I also ordered the Venom 400. Anybody have any experience with any of these products? The truck is otherwise stock and runs like new (only 108K miles). Thanks.

95SASMudRunner

been looking at the rear disc conversion for some time but have yet to break down and buy it. let us know how it goes

BigBluePile

iTrader: (3)

Here's what I did:

http://www.4x4wire.com/toyota/reviews/rear_discs/

and

http://www.4x4wire.com/toyota/reviews/parking_brake/

I don't use my VLSV(?) so I put in a proportioning valve (http://store.summitracing.com/partde...&autoview=sku). Installation was a breeze and is by far one of the best mods I've done, especially on 35's. However, if I was going to do this over again I'd do this:

http://frontrangeoffroadfab.com/nfos...3825d03234e406

My rear end locks up pretty well when I jam on the brakes, but that's to be expected. I have my proportioning valve turned up a little high. I'm also running a bigger master cylinder with a 1" bore instead of the stock 3/4" one. I know that this isn't the Downey kit, but I'm sure it all installs the same! Just becare cutting the backing plates off!!! I would use a press and go that route, but cutting is so much easier!! Good luck!

04 Rocko Taco

I keep thinking about a rear disc setup for my truck, I rarely use my e-brake anyway...but I just dont know, I cant talk myself into it...

BigBluePile

iTrader: (3)

I wasn't either, but the transfercase ebrake is great!!!

TOYROTAROB

The backing plates for the drum brakes appear to bolt off after removing the half axles from the rear end and removing the "C" clip from behind the backing plate. The Downey instructions also indicate this to be true. You sure I'll have to cut them off? No where is cutting mentioned. I guess I could take them to a local shop and get them pressed off if I need to. Anybody? Also, the OEM proportioning valve says it's got some adjustment so with that and the new one provided with the kit you should be able to get the right split of pressure front to rear. You have hands on so you know better than I. What year was your vehicle? Maybe it's different on mine. Anybody? Keep the info flowing cause that's what make these forums great.

BigBluePile

iTrader: (3)

You have to get the backing plates off in order to bolt on the new brake caliper braket. Some people have modified their backing plates to still use them. Most of it still gets cut off. I have an 1986 4Runner. Your 1994 rear axle should be the same. The only difference is the snout. You can press off the rear wheel bearing and pop off the entire backing plate, then repress on the wheel bearing and carrier. If your reeeeeeeeeeeeeeeeaally careful, you can cutoff the backing plates. It's not the hard, a good grinder makes short work of it. Just don't hit any parts of the axle. Again review this "how to" and you'll (hopefully) understand what I'm talking about:

http://www.4x4wire.com/toyota/reviews/rear_discs/

Here's what I mean about "modifying" the backing plate:

http://www.4x4wire.com/toyota/reviews/fullfloater/

I don't use my stock proportioning valve anymore, I had to do some replumbing to bypass the LSPV (my FSM has adjustment procedures if you plan on keeping it).

FredTJ

The rear locking up is almost completely due to the rear bias that you've dialed in with the prop. valve and really doesn't have much, if anything to do with the lager MC.
The larger MC supplies LESS pressure than the smaller one did. Laws of fluid dynamics

When people swap to a large MC they'll often think that they have more braking power because of the increased pedal feel, but that increased pedal resistance is due to the lesser pressure that the large MC is creating, thus requiring MORE pedal pressure to achive the same pressures and the smaller MC.



Fred

BigBluePile

iTrader: (3)

The reason I swapped out the MC was because the stock one doesn't have the residual pressure for the rear brakes like the front (plus it was 18 years old at the time). I could have used the original(with 13/16" bore not 3/4"), and put in a residual valve to the back end and been good to go. Hmmmm, guess my Physics is rusty. Larger surface area pushing fluid down same size hole. Should be more fluid flow right?

isaac338

old thread i know, but i believe your assumption is wrong. a bigger piston in a master cylinder will create less pressure at the caliper. it's a ratio between the two sizes - 1lb of pressure on a 1 sq in master cylinder will make 2lb of pressure on a 2 sq in caliper. 1lb of pressure on a 2 sq in master cylinder will make only 1lb of pressure on the same caliper. the same setup but with a .5 sq in master will = 4lb pressure at the caliper.

... if i remember correctly.

FredTJ

You remember pretty much correctly.
Larger diameter MC (bore diameter) = LESS pressure for the same amount of pedal effort however the pedal feels firmer because it's now harder to press down. That firmer feel is what a lot of people mistake for more pressure when, actually, it's less pressure..




Fred