Master cylinder upgrade to 2 chamber style

[lostviking]

The Toyota is a slightly different bolt circle. I used a couple drills to step the holes up until I was able to bolt it into place (46 Dodge WD15). I forget the exact drill I ended at, but I was just hitting the inside of the aluminum with the bolts. It leaves plenty of meat in the mounting flange on the master cylinder.

[Matt Wilson]

1 hour ago, lostviking said:

The Toyota is a slightly different bolt circle. I used a couple drills to step the holes up until I was able to bolt it into place (46 Dodge WD15). I forget the exact drill I ended at, but I was just hitting the inside of the aluminum with the bolts. It leaves plenty of meat in the mounting flange on the master cylinder.

Ok, thanks!  I had to go to the parts store for other things just now, and I asked them about this master cylinder.  They didn't have it in stock, but I went ahead and had them order it, and they should have it in store later this afternoon.  If I can't use it, then they'll take it back at no charge.  I made a trace of the bolt pattern from my original master cylinder, so I'll take that with me to compare.

 

The only other thing that occurred to me is that the Toyota part won't have the stub sticking off the back end, where the rubber dust boot goes, so the back of the new cylinder will be open to dust, water, etc.  I may have to rig up something to accommodate the boot so that the system stays closed.  That was one thing about the Wilwoodaster cylinder - it had a stub that perfectly fit the boot.

[bkahler]

Matt, my apologies.  I got side tracked after work yesterday and forgot to look for the info.  I will look this evening....

 

 

[bkahler]

Ok, when I worked out the dimensions for the adapter plate to bolt a Wrangler MC to the bell housing I came up with 2.625" between mounting holes.  So if you measure center to center between any two mounting holes you should get 2.625".  That works out to roughly 1.5175" from center of MC to center of any of the three mounting holes.  When I fabricated the plates I laid the dimensions out in X Y coordinates so I could use my mill to locate the holes.  The plates came out just fine and lined up with the holes on the bell housings pretty much right on.

 

I hope this helps

 

Brad

[Matt Wilson]

4 hours ago, bkahler said:

Ok, when I worked out the dimensions for the adapter plate to bolt a Wrangler MC to the bell housing I came up with 2.625" between mounting holes.  So if you measure center to center between any two mounting holes you should get 2.625".  That works out to roughly 1.5175" from center of MC to center of any of the three mounting holes.  When I fabricated the plates I laid the dimensions out in X Y coordinates so I could use my mill to locate the holes.  The plates came out just fine and lined up with the holes on the bell housings pretty much right on.

 

I hope this helps

 

Brad

Thanks, Brad.  I was actually looking to find the bolt pattern of the Toyota master cylinder, but I'm glad to see that your dimensions for the original Dodge master cylinder bolt pattern agree with what I measured on my '49 Power Wagon.  My apologies if I wasn't clear on what I was looking for.

 

I went ahead and bought the Toyota master cylinder that was listed by Rocket-bob (p/n NM55022, which fits a 1992 - 1994 Camry) and it is very close to being a match to my Power Wagon bolt pattern and yours too, it seems.  As lostviking said, I'll need to open up the bolt holes a bit, from their current 0.36" (actually metric, I'm sure) to 13/32" (0.406", approximately), which is the bolt hole size in the original Dodge master cylinder.  As best I can tell, I'll also need to offset each hole by a small amount (I think I came up with 0.060 or 0.080").  I don't think any of that will be a big deal. 

 

The whole unit, reservoir and all, is narrow enough and short enough to fit into the tight space between my frame rail, the brake pedal and the steering box.  One outlet comes off the left side of the unit, which concerned me with regard to interfering with the frame rail at first, but looking at it some more, it seems like there is enough room for a sharp bend or a 90-degree fitting to allow that line to head where it needs to go.  The other outlet comes straight up, so it won't be a problem.

 

The rear of the Toyota master cylinder has a circular stub sticking out rearward, which is a little smaller in diameter than the stub on the original Dodge part, and this is where the dust boot fits.  I imagine I should be able to find another boot to fit this Toyota part, or come up with some way to make something work to keep out the dust, water, etc.

 

Thanks again for the help.

[Rocket-bob]

Seems like a run away topic while I was dealing with COVID.  I used the Toyota Master Cylinder on my 1952 Dodge B3C so I can't talk to other master cylinders or vehicles.  For me, it was a direct bolt in except for slightly enlarging one hole.  I went back through my photos and have attached a couple that shows the hook up.  These photos were before the brake lines were run and before the warning light was hooked up.  I can't seem to locate the later photos.  Anyway, I used the original dust boot and a slightly shortened original push rod.

 

 

[lostviking]

Here is a picture of mine installed, and another with a PV2 proportioning valve attached and mounted.

[lostviking]

Here is the proportioning valve attached and the two just sitting on my work bench.

[Rocket-bob]

Lostviking

 

My setup is practically identical except the addition of 10lb residual valves.  Looks great.  I hope yours works as well as mine.

[lostviking]

I talked to the people at Scarebird. I went over the complete system with them, and they said I wouldn't need residual valves.

[Matt Wilson]

On 12/29/2021 at 3:15 PM, Rocket-bob said:

Seems like a run away topic while I was dealing with COVID. 

 

23 hours ago, lostviking said:

Here is a picture of mine installed, and another with a PV2 proportioning valve attached and mounted.

Rocket-bob and lostviking, thanks so much for your info and photos!  And Bob, I hope you've fully recovered now from covid.  Not much fun, I hear, if you have any significant symptoms.

 

The info from you both is very helpful.  This gives me confidence that I'll be able to make the Toyota part work on my truck, and I had been wondering about a proportioning valve.  I suppose it's best to buy an adjustable one?  If that's what you did, then what pressure split did you choose, and how did you arrive at that value?

 

And if I understand correctly, residual pressure valves are only needed if you plan to use disc brakes on one or both axles.

Edited December 30, 2021 by Matt Wilson

[Rocket-bob]

As stated early on, I ran a CCP proportioning valve because I had a modern rear axle (though drum brakes) and the '52 brakes on the front.  I wanted to be able to dial in brakes between front and back.  I don't know what pressure gradient I used, I simply drove the truck and did some hard braking in curves to see if the rear got loose.  I made a small adjustment but the brakes were about fine from the start.  I would like to replace my front brakes with disc brakes but that is a later issue.

 

I used the residual pressure valves to keep fluid in the lines.  The goal was to remove pedal travel and snap back.  While the clutch has a spring attached to keep it in a neutral position, the brakes do not.  You can actually slam on the brake, have your foot slide off and the snap back can pull the guide rod out of the master cylinder.  The residual valves cut down that snap back and the pedal travel.  

[Matt Wilson]

1 hour ago, Rocket-bob said:

As stated early on, I ran a CCP proportioning valve because I had a modern rear axle (though drum brakes) and the '52 brakes on the front.  I wanted to be able to dial in brakes between front and back.  I don't know what pressure gradient I used, I simply drove the truck and did some hard braking in curves to see if the rear got loose.  I made a small adjustment but the brakes were about fine from the start.  I would like to replace my front brakes with disc brakes but that is a later issue.

 

I used the residual pressure valves to keep fluid in the lines.  The goal was to remove pedal travel and snap back.  While the clutch has a spring attached to keep it in a neutral position, the brakes do not.  You can actually slam on the brake, have your foot slide off and the snap back can pull the guide rod out of the master cylinder.  The residual valves cut down that snap back and the pedal travel.  

Ah ok, good info, thanks.

[lostviking]

On my 46 WD15, there is a return spring on the brake pedal. Also, the rod can't come out of the master cylinder unless I go under there and slack off the adjustment on the rod length itself. I have disks on the front and drums on the rear. The PV2 is designed for that, and is not adjustable. I must point out, that I have not driven the truck yet, as there are still things to finish.

[Rocket-bob]

1 hour ago, lostviking said:

On my 46 WD15, there is a return spring on the brake pedal. Also, the rod can't come out of the master cylinder unless I go under there and slack off the adjustment on the rod length itself. I have disks on the front and drums on the rear. The PV2 is designed for that, and is not adjustable. I must point out, that I have not driven the truck yet, as there are still things to finish.

I would love to see the return spring setup. I have considered creating one but have see the clearance with the cab. 

[lostviking]

Page 5-9 of the parts book. Item 25.

Edited January 1, 2022 by lostviking

[The Oil Soup]

Mine has a return spring on the brake pedal also. I used a master cylinder and proportioning valve from a ‘93 Jeep Cherokee.