57 3100 4-speed Disc Brakes

[Ghetto Fireman]

Hello All:

I have a 1957 3100 with 4-speed manual transmission. I’m adding a drop axle from SIDS along with 2 1/2” dropped front leaf springs. Planned on upgrading to discs up front but I’m finding out that the kits available won’t work with a four speed manual ? Does anyone know a solution to this? Can I go with a non- booster master cylinder? It’s my understanding that the 4-speed transmission cross member interferes with the frame mounted master cylinder. Anyone done this conversion?


Thanks

Mike

[mongocanfly]

"Planned on upgrading to discs up front but I’m finding out that the kits available won’t work with a four speed manual"
...I don't follow you...
are you saying disc brakes wont work with a 4spd trans?...
the transmission has nothing to do with disc brakes...

"Can I go with a non- booster master cylinder?"
you can use a non-boosted master cylinder...but power brakes are nice to have

[Dan in Pasadena]

^^^ Me too^^^ I don’t understand the connection you’re making.

You have a half ton so upgrading to discs with either 5 or 6 lugs should be easy, there are a number of aftermarket kits offered. Now it may limit your use of 15” rims, but even that is a maybe not a certainty.

[Ghetto Fireman]

Sorry, I’m told that the master mounted in the stock location on the frame won’t work with a 4-speed manual transmission?

[mr48chev]

"Told" by who? The problem would be a clearance issue under the floor.

I'm going to assume that the kit that you are looking at comes with the pedal assembly and that is the issue as those do not have provisions for a clutch pedal. The fix for that is to find a booster/master cylinder with a bracket and no pedal assembly and use you stock pedals.

This is only an EXAMPLE and not a suggestion that you buy this specific one. The same outfits that sell the whole kit with pedal usually sell the same small diameter booster and master cylinder assembly that you can fab a bracket for and by building a stronger push rod (beefy) you can mount the assembly under the truck and use your original pedal. A few on here have done it on TF trucks and when they wake up maybe they will be kind enough to show the photos of what they did and explain how they did it. https://www.ebay.com/itm/1960-1966-C....c100005.m1851

The manufactures of those kits with the pedal all think that we all run automatic transmissions.

[mr48chev]

Here is what they say is a bolt on kit that will fit your truck. Note, they say there may be crossmember clearance issues. https://www.classicparts.com/1955-59...ctinfo/71-907/

[Ghetto Fireman]

Thanks for the reply, I’d like to keep the original brake pedal. Wondering if I go with a dual master without the booster if I’d still have issue with the cross member. I was hoping that someone had done this on a 57 with a 4-speed manual.

Appreciate the response !

Mike

[mongocanfly]

"Sorry, I’m told that the master mounted in the stock location on the frame won’t work with a 4-speed manual transmission? "

ok..makes more sense ...from what you posted it read as if a 4 speed wont work with disc brakes

[mongocanfly]

just remember ..."anything" can be made to work with enough willpower...

[sack54]

The under cab master cylinder will bolt on fine and you can use your stock pedal, I just installed the unit into my 56 GMC bolted right in even with my 4 speed transmission. There is plenty of room. If you had three on the tree you would need new cross member, that is what the company told me ,had same concerns as you do.
Got the one I used is from Brothers truck Parts

[dsraven]

we are assuming your truck is a stock 6 cyl with a stock 4 speed trans, stock pedal assemblies?
if you want to go with discs up front you would be well advised to go with a power brake unit as well simply because most other cars on the road have power brakes so they are gonna stop quicker than you and the chances of a rear ender with you to blame is more.it is basically the same amount of work anyway because you will need to change the master cylinder to be disc front drum rear and a dual system. you need to seperate the front and rear brake systems so that means some new brake lines to connect to the master and possibly some proportioning valve work or residual valves (more important with the frame mounted master because the master is more level with the brake wheel cylinders and calipers so a 2 lb unit may be needed to keep a slight pressure in the wheel cylinders, check with the supplier). a master cyl for drum brakes usually has a residual valve built into the master cyl so you may want to check the kit you buy to see if that is the case.
if going with power brakes you will need a vac line with a check valve to the booster, but the check valve is usually in the fitting at the booster. a lot of guys like to go with the hydro boost for power brakes because it is a smaller system, physically, so less space required under the floor and great boost. it may be hard to hook up if you don't have power steering though because it runs off the power steering pump. if going with vac booster you will be looking for the dual diaphragm style similar to the old corvette units because they are physically smaller as well but the dual diaphragm still gives good boost. not sure how much power boost you get compared to the hydroboost or a larger single diaphragm vac booster but if you wanna keep it under the floor then you are limited for size anyway unless you mount it further back on the frame and run a long push rod (see kim57 thread for what he did. he used a hydro boost but the theory is the same).
anyway, post up some pics when you start. a good kit would include the correct master cylinder (disc/drum)
master cylinder mounting bracket and hardware
disc conversion hardware, rotors with bearings, seals etc, pads, caliper mount brackets, nuts bolts etc
calipers, banjo bolts, copper washers, frame mounts for the hoses, hose retainer clips etc
front brake hoses
residual valves as the supplier sees fit
proportioning valve as supplier sees fit


here is a quick run down of a kit installed with rotors that fit over the original front hubs, so 6 bolt.
http://www.hotrod.com/articles/0902c...g_sanding_disc


here is one from cpp but not good for dropped spindles

https://www.classicindustries.com/pr.../pb10217a.html


http://www.bobschevytrucks.com/brake...nversion-kits/

[Ghetto Fireman]

Originally Posted by sack54

The under cab master cylinder will bolt on fine and you can use your stock pedal, I just installed the unit into my 56 GMC bolted right in even with my 4 speed transmission. There is plenty of room. If you had three on the tree you would need new cross member, that is what the company told me ,had same concerns as you do.
Got the one I used is from Brothers truck Parts

Thanks for the reply, I went to the Brothers website and looked at the frame mounted booster, bottom line under NOTES says this will not work with manual transmissions. Nice to hear from someone who has experienced it first hand. Looks like I’ll be ordering one.

Thanks

Mike

[mr48chev]

I am pretty sure some of the guys have photos. It just takes a bit of time for the to see the thread some times.

That booster kit from classic parts may solve one issue as it appears that the lever setup multiplies the distance the pushrod to the booster moves. It also solves the direct line push thing.