Olds Dad

Ok - Here it goes

The OE Treadle Vac is dying on my driver, so I've been doing some research on converting this to a modern master cylinder / power booster. First of all, safety is a concern - upgrading to a dual reservoir master is just smart - stopping a 4800 pound leviathan with a hand brake doesn't sound fun. Secondly, these TreadleVacs aren't cheap - I'm looking at $400 for one and I can do most of what I want to for about the same change.

Here's the catch - I want this to be a trial run for my full-on restoration job of my '55 Super 88 Holiday Sedan - so I don't want to use the firewall mounted, hanging pedal setup.

So, my preliminary research indicates that I can physically bolt a 7" diameter single diaphragm booster with a dual reservoir, remote fill master cylinder in the toe pan plate of the car.

I found a thread where a guy did a similar conversion on a '56 Packard (they used the same TreadleVac except they called it "Easamatic"). I'll get into more detail later, but I actually contacted him and asked some questions - stopping power, valving, pedal ratio, overall satisfacation - etc..

In short, he did some modifications to his pendicular pedal (same essential setup as our OE pedals) and he's 9 years into using it and couldn't be happier.

Step 1 was getting the car off the ground and removing the driver's side inner fender well for access.

My measurements seem to indicate that I'll be ok.

Here are a few pics of the unit and some overall dimensions - the TreadleVac is about 5.5 inches in diameter - so the 2" clearance I have to the steering column should allow for a 7" to go in as well. The overall length of the Treadle is about 12" - the booster / master setup I'm looking at will be 11.5

Also note that I plan to do a front brake disc changeover at the same time.

Stay with me and maybe I'll get through it - or maybe I'll be parting it out in a month...

59-59-59

I don't understand why a company will make a bolt on disc brake conversion kit, yet they are scared to produce a true bolt in master cylinder for them. I'm taking about the pre' '61 full size Olds. I would like to see this done to your car, as the only ones I've seen we're firewall mounted

Olds Dad

Yeah - it's frustrating. Even the guy at MP Power Brakes was hesitant to help me. I gained a lot of confidence after communicating with the guy who did the conversion on the Packard - very similar circumstances and almost identical setup. Part of the reason I'm starting this thread is to hopefully help others in the same boat.

redoldsman

I will be following this one closely.

rocketraider

The street rod guys should have this covered. Plenty of their cars originally had underfloor M/C and I've seen plenty of kits that mount the booster and m/c under floor. Ground clearance may be an issue for the booster, but it can be done.

CR*71

I'm very interested in following your progress. I have a '53 98 that I bought with the brakes disassembled, so I'm trying to figure out what to do before I rebuild...go with original setup or switch to disc brakes. I also want to keep the under floor mount as my autronic eye is mounted on the firewall where the master cylinder would normally go.

m371961

I know the street rod guys do this all the time. Try looking at a Speedway motors street rod catalog.

Olds Dad

The street rod guys either use a hanging pedal and a firewall mounted master, or a complete under the seat system that uses a crazy linked brake pedal - mine is in the toe pan and I intend to use the OE pedal assembly, so it's a little different - the intent is to keep as close to stock appearance as possible.

Olds Dad

Removed the pedal assembly, the toe pan plate, and the Treadle Vac unit.

As you can see from the photo of the pedal assembly (noting the pencil is where the master cylinder push rod engages), you can see that the OE assembly only yields a 1:1 pedal ratio. I need a 4:1 to make this work.

I knew going in that this was going to be the biggest challenge. I have some ideas to change the pivot point of the pedal, and I have room to lower the pedal a couple of inches - but quick and dirty calculations show a 2.5:1 at best - so here's the part where I'm open to suggestions.

I'm bringing the assembly to a custom car guy tomorrow (have to go there for other reasons, but figured...), so maybe he'll have an idea or two - in any event - I have to wait for parts before I do much more anyway, so I may as well play with this.

Hope the photo titles explain what you're looking at.

SIDEBAR: Any opinions on whether to retain the auxilliary vacuum canister for this? Modern cars don't have them - i wonder if only the treadles were sensitive to a minor loss of vacuum - and provided I have the main vacuum, I should be ok?

Olds Dad

Ordered Master & Booster today...

55miketn

I have a '29 for A pickup roadster streetrod and have a under the floor master cyl. and 4 wheel disc brakes. NO PROBLEM! I also have a '55 olds s88 with the moraine brakes. Rebuilt but not quite what I would like. I think the bolt on m/c and booster are a great idea and don't see a real problem. The remote m/c fill is the best way to go. I'll be keeping up with this. Thanks!

WHIPOLDS

Gordon - I am watching this one also. Have had many brake issues over the years with the Moraine unit. I had the wheel cylinders brass sleeved and the Moraine unit rebuilt about 7 years ago and have had no real issues since, except when the car sits over winter. Even so the brakes are not what I would really call good.Thanks for posting on this.
Rick

Olds Dad

I removed both front spindles yesterday - as part of this project, I'm doing the front disc converstion as well - but upon disassembly I noticed that the kingpins were fairly worn - bringing the spindles to a local machine shop to have the new ones fitted / burnished / reamed.

Got my conversion bracket from Mike Pemberton (discbrakemike.com).

Awaiting booster / master / valves, etc...

Olds Dad

All parts have arrived - still waiting for the spindles with new kingpins to come back from the machine shop.

Hopefully will do a dry / test fit of the booster & master cylinder either tonight or tomorrow night. Will post pics when I do (assuming it all fits as planned and I haven't lit the car on fire out of frustration)

55super88

Gordon, i too will be watching this tread as would like to change to more modern booster and daul res. master ,thanks for your post

Olds Dad

OK - So I had a fairly successful night. I got the new booster and master cylinder fitted on the floor plate - I had to slightly modify the original hole in the center of the plate (where the pushrod goes through) - but that was more due to my apparent inability to use a measuring tape.

So, I haven't yet bench bled the master, but I dry fit the entire assembly into the car....and VOILA! It fits! It seems that I could have used a LH outlet port master after all, but I've still got more room on the right. VERY close to the frame at the front of the master cylinder - maybe a half inch to spare, so I'm certain now that a dual diaphragm booster would not have worked.

In my mind, there are two major obstacles to overcome in this project. The first was this dry fit - so far, so good.

The second will be modifying the brake pedal to achieve the 4:1 mechanical advantage (pedal ratio) that is recommended. I think I'll be able to get close to that, but that is task number two - will start on that tomorrow night (Friday is my my "official" garage night) -

If that goes well, everything else is just plumbing!

Fingers crossed.

55super88

Gordon, looking good, are ya keeping good notes on the parts used and part numbers and year car we will need parts from and modifications ya needed to do to fit. I was looking at your pics hows the ground clearance, and how do you like the mikesbrakes stuff any pics of it would be great thanks for the help and info

Olds Dad

Yes, assuming complete success, I'll post a breakdown of everything I use.

The ground clearance is essentially the same as with the OE unit - perhaps even marginally better.

Olds Dad

presently stumped by the pedal ratio aspect...will revisit tomorrow (with less than a few octoberfests in my viens)

59-59-59

This is exactly what Journey With Olds needs. It would be great to send in this technical stuff so some of the other guys could see what is needed for this swap

Olds Dad

While I'm still waiting for the spindles to have the new kingpins fitted, I've done some more work on the pedal ratio piece.

After exhausting every avenue with the OE pedal arm assy, I've determined that if I could fit it, it would be way left and low with respect to the gas pedal.

I found some 1 in. square steel tubing and some plate steel and made this mock up for a new pedal arm that will pivot just above the pushrod (~1.5") and hang below by about 6" giving me an approximate 6/1.5=4:1 pedal ratio.

I'll be able to weld this pivot to the exising brake pedal mounting plate allowing it to be removed from the car separate from the floor plate to which the booster is mounted (similar to how it's set up originally) -

I need to tack weld it in place and put back in the car to make sure the "feel" is ok, but I think the "POWER BRAKE" pad, in the approximate location shown, will be pretty good.

I'll weld a plate to accept the old pedal pad - and after all's painted and cleaned up, it should look ok - especially to the untrained eye.

Assuming this works, my final challenge with respect to the pedal will be fabricating a linkage to actuate the brake light switch -

Olds Dad

Got the pedal swing arm mounted tonight and did a brake pedal mock up. Note that after I took these photos, I set the assy in the car and all is great except that the brake pedal is too close to the gas pedal, so I'm glad I only tacked it.

I'll move the pedal pad to the centerline of the pedal swing arm and I'll be fine. Getting a 4:1 ratio now and once I'm locked and loaded here, I'm going to permanently mount and start the plumbing from the master.

I'm now getting excited about this - I think my major obstacles are close to being overcome and if a hack like me can do this, I think anyone can.

55super88

looks like your making head way, small gains at a time, good job

Olds Dad

Final fit up - this is the position that I'm going to run with unless ultimately (after some use) I realize it doesn't work - but seems 'comfortable'. If you got in the car and had never driven one of these before, I don't think you'd even think anything of it.

Only thing left to do is to fit up a linkage / bracket for the stop lite switch to be actuated.

Started fitting up some combination valve plumbing too, but more on that later after I figure it out.

Tedd Thompson

Gordon,.

Looking good! I'm following this with major interest. You will make this conversion easy for the ones who follow in your steps.....Tedd

Olds Dad

Thanks Tedd - kind of a fun project - taking me away from my 2 dr sedan resto, but if I don't fix the brakes on this one now I'm afraid it will sit too long and I'll lose interest...

Olds Dad

Combination valve was designed for the typical LH port master cylinder - since I needed the RH port due to the location of the assy, I had to mount it on the opposite side (mirror image) - had to re-plumb the lines since the Front was now the rear and so on...got confusing so I had to mark "R" and "F" in the right spots...a $25 double flare kit at AutoZone and used the fittings from the combination valve kit.

This does fit in place with the valve mounted as shown -

55super88

Keep up the nice work, you got me on the edge of my seat following your progress

Olds Dad

Will post photos later, but got my stop light switch linkage all welded up and painted the pieces for a permanent install.

Balance of disc brake conversion stuff will be here Tuesday - I'm thinking next weekend this thing should be rolling

Olds Dad

To make the Stop Light Swith work, I cut off the switch pad bracket (with the adjustable nut) from the original brake pedal arm.

Next, I used some plain 1/4" flat bar stock and basically clamped it together to get to the stop lite button (which I retained in it's original bracket and location) -

As you can see, I ended up adding the spring - the pedal returns fine on it's own, but there was that last little gap I couldn't seem to close between the bracket and the switch button no matter what I did - so the easiest thing was to add the spring - that way I'm not driving around with my brake lights on all the time

Just need to figure out how to bench bleed a remote fill master cylinder (seems like it'd be different from a conventional master) - and we're going forward.

Olds Dad

Just a few pics of reassembling my king pins / supports / spindles.

K-90 King Pin Kit from Fusick includes new bearings and shims, as well as the pins, bushings, and end grease caps.

Figured the setup might help someone thinking of doing this...Taking them off the car is very simple (Don't even need to compress the coil springs) - and if you have the bronze bushings fitted by a machine shop, the reassembly is simple.

Olds Dad

Still plugging along..

Two quick pics of the disc brake conversion part.

The whole process is going slowly, but I'm moving forward - I hope to get back to the power brakes part of it today.

Olds Dad

Permanently mounted the reservoir, booster/master/combination valve assembly, and the residual pressure check valve to the rear brakes. All lines from the master to the rear wheels are now replaced.

All that is left is to replumb the two front wheel lines from the master and it's ready to bleed.

Olds Dad

Plumbing is complete. Decided to put one 2 lb. residual valve and then tee, rather than 2 separate valves to each wheel as I originally intended (mostly for simplicity and location) -

Have one side of the disc brake assembly installed with new line and hose as well.

One more spindle to reinstall and I'm on to bleeding and road test..almost there!

55super88

take your time and do it right the first time Good job my freind

Olds Dad

SUCCESS!!!!!

Yesterday I got a rare full day on the car (wife & kids were gone for the day) - Put all the little things back together (wheel well, stop lite switch etc..) and bled the system with the help of a hand held vacuum pump, and later a friend who today has a sore calf from brake pumping I'm sure.

Road Test:

Took it out on some rural roads to do some hard braking. 60-0 stop is significantly better than it was on the old system's best day - tracked straight and true, no pulling no fading. The car behaves as a car should - no nose diving, no premature lock up.

I think I might try to adjust the push rod a hair longer - when I stand on it I'm at what I would consider "impending" lockup - but no lock up - I think I need a hair more travel in the master piston. I may not mess with this because it certainly seems to stop as good as any modern car, and as quickly -

As for 'feel' - pedal effort is EXACTLY as it should be - normal foot effort - position as I've modified 'feels' completely normal, and as you can see in the photo, looks almost factory -

Going to take her for a 75 mile trip today and see how I feel then - but I venture to guess she'll be fine.

I will post all the part details tomorrow (my paperwork is at my office), but I'll say this -

This project is fairly involved (took me about a month), BUT is very do-able for most guys who consider themselves mechanically inclined. Biggest obstacle was the pedal assembly modifications -

If you follow what I have done, you will be successful

Short summary:

7" Booster (single diaphragm)
Remote reservoir master with RH outlet ports
Combination valve from Speedway Motors
Disc Brake Mike disc conversion setup
2lb residual pressure valve to the front lines
10lb residual pressure valve to the rear lines
All rear lines were kept as 1/4" due to OE Tee and Wheel Cyl Fittings
Front lines changed to 3/16" due to modern hose fitting size and combi valve sizes.
I kept the vacuum reservoir for the heck of it.

You will need to remove the driver side fender well for access, but everything else can be done from either inside the car or underneath.

I'm happy to try to answer any questions -

In short, if I painted the booster and master black, you'd never know the system was there.

WHIPOLDS

Gordon - Glad to hear that your project turned out so well! Thank you for posting the details.

Rick

55miketn

Don't remember whether you used a proportioning valve or not?? You said it didn't nose dive, and I would have thought it would a little? Looks like a great gob and the info. is greatly appreciated; especially the pictures (them being worth a thousand words and all).

Olds Dad

Yes I did - see Post #27 picture - used a 'combination' valve, which 'combines' a metering valve and a proportioning valve in one unit. I contemplated not using it, but in the end I feared that if I found out later I needed one it would be a lot more work to go back and try to retrofit it - rather than just installing from the outset.

55miketn

OK. Went back and looked at all the pics.. GOOD JOB. Did the top for the master cyl. come with it or did you have to make it? (for the remote fill)