Another brake story

[oldodge41]

It is really cold here today. 8 degrees F as a high so far. Too cold to bother heating the garage to work on my brake project. So, I will bore all of you with some insight on what I am up to this winter.  Upgrading to a dual-circuit master cylinder on my '41 Dodge Business Cpe.

A little history. The car is a true barn find, drug out of an old chicken coup in 1990 by my Dad and I. We rebuilt everything our selves and have driven it since 1991. Not a show car, not a rat rod style car. Just a fixed up old car. A few years ago I had a brake problem and ended up having my front wheel cylinders sleeved and replaced my 1 1/8" master cylinder with a sleeved 1" unit. A few years later I swapped to a Ford 8.8" rear for better gearing and of course that changed my rear brakes as well.

My goal for this project was to install a dual circuit master cylinder on a low budget keeping in mind a possible disk conversion on the front in the future while retaining the ability to return to stock if I ever wanted to.

The project began by jacking up the car and securing all four corners on jack stands. Safety first. I then removed the front floor pan section from the cabin. Next came removal of the master cylinder and all of the hard and soft brake lines. I then put the original setup in the vice and started measuring.

[oldodge41]

I wanted to build a bracket to mount the pedals and master cylinder on, similar to others shown in other threads here. I also considered leaving the original master cylinder in place and running a rod thru to a new master cylinder. This would have made access to the m/c under the seat. I then considered a longer shaft with the m/c located far enough back to be accessed from behind the seat. In the end, I built the bracket to replace everything. Not one particular reason other than I just wanted to. I built it out of 3/16" flat steel, some angle and a piece of 3/4" pipe I had laying around. The id of the pipe was just slightly large for my .750 shaft so I made an inner sleeve of thin aluminum flashing to make a better fit. Please be nice, I am not a welder or professional fabricator. I am just a shadetree mechanic, but I am proud to be one.

[Merle Coggins]

It is really cold here today. 8 degrees F as a high so far. Too cold to bother heating the garage to work on my brake project...

-2 here this morning and I was out in the garage putting brakes on the Fiancé's car. Had my propane twin burner Mr Heater going to take the edge off. Not ideal work conditions but it needed to be done.

[oldodge41]

Next up, what m/c to use. Wow, I had no idea how much info, contradictory info even, I would find on this topic. In the end I decided to figure the total area of my wheel cylinders and try to match a m/c bore size to other vehicles with similar wheel cylinder total area. Flawed logic? Probably, but I had to decide on something. I then looked for a m/c with a disk brake reservoir for the front in the bore size I wanted. I came to the conclusion that a 1" to 1 1/16' bore would work. I wanted something I could bolt to new bracket and the outlets would be on the correct side for ease of plumbing. I ended my search with a Raybestos part # MC36412 with 1 1/32" bore, designed for the following applications with manual disk/drum brakes.

DODGE ASPEN 1976-1977 DODGE DART 1973-1976 PLYMOUTH DUSTER 1973-1976 PLYMOUTH SCAMP 1973-1976 PLYMOUTH VALIANT 1973-1976 PLYMOUTH VOLARE 1976-1977

Due to the gusset I welded on my bracket not allowing access to a nut I decided to use the upper mounting hole under the gusset with a permanent guide pin that I welded to the bracket. It just helped lining up the MC when putting it on the bracket. I then trimmed the mount of the m/c to fit the bracket and drilled holes diagonally from each other and bolted with grade 8 hardware. I used grade 8 hardware on everything. 

Edited February 13, 2016 by oldodge41

[oldodge41]

I ran into some issues with pedal spacing side to side which has been addressed in other brake threads and I overcame it by offsetting the plunger from the pedal a little to allow for the width of the master cylinder. I put it all together on the bench and bled it before final mounting in the vehicle. I had it in and out of the car a fair amount of times tweeking on the setup before calling it good and bolting everything up. I had to cut a very small notch in the permanent floor pan to allow the corner of the m/c, which is larger than the original, to set in place. Also higher than the original, it protrudes above the floor about an inch, so I made a new raised cover to provide access to the MC. I also had to enlarge the hole in the removable floor pan to make removal of the m/c cap easier. I now have it bolted up and noticed when pushing on the brake the bracket flexed ever so slightly from the frame. I had read about the possibility of this on another thread here and thought about adding a fourth bolt to the bracket to eliminate it. My drill didn't fit squarely between the frame and transmission and I don't have an angle drill, so I just tack welded the upper front corner of the bracket to the frame. A quick grind with a 4" grinder is all it will take to remove it if I ever need to. Had I made the bracket from 1/4" steel versus 3/16 the flex may not have been noticeable. I don't know, but it would have offset my pedals even more with a thicker bracket. Everything is bolted up, I put 10lb residual valves on both the front and rear lines. The real is all plumbed with new lines and a new brake hose. I used one for a '93 Ford Explorer since that is the rear differential/axle used and it took the 3/16" brake lines both in and out eliminating any adapters on the rear. Les fittings equals less possible leak points.I plumbed the front to the distribution block / brake light switch with 3/16" line using an adapter at the distribution block to adapt to the 1/4" tub fitting size of the block. I have started routing the front lines from the distribution block with 1/4" tubing, again to minimize use of adapters to new flex hoses. Once this piping is done I will bleed and adjust the brakes and try it all out. I will let you know how it works, or if it fails. 

[50fordtruck]

I have a high of 10 below today.

[oldodge41]

I feel for you Merle. If I had to do it, I would do it too. But, this project creates no urgency.........yet.

[casper50]

In Alaska this morning it's a sunny 34F.  Has been upper 20's to 40 since new year.  nice job by the way.  

[dale]

You can buy a double master cylinder with a vacuum booster and padels that attaches where the old master cylinder for around $250...

[oldodge41]

Update: I ended up replacing all the steel and rubber lines. Replacing the steering box bottom seal and replacing all four tie rod ends while I was at it. I was having trouble getting the brakes bled. I had good stopping power but a low and spongy pedal. I bled as I always have with one person on the bleeder and one on the brake pedal where you push down pedal, crack bleeder, when pedal hits floor close bleeder, release pedal, repeat. I could not get all the air out. I thought I did, but obviously didn't. I then got a vacuum bleeder and used it with limited success. I then read the "41 Dodge service manual. I know, I know, it should have been first, but I have never had this problem bleeding these or any other brakes my way. Besides, my wife says it's because I am a man and I know everything. Yeah right! The manual said to attach a piece of tubing to the bleeder with the other end in a container that contains enough brake fluid to cover the end of the tubing, open the bleeder, push the brake pedal down 1/2 way six or eight times, close the bleeder  and check fluid level. I did one wheel and the result was instantly noticeable. I had my wife come out and pump the pedal for me so I could watch the tubing and I was amazed at the amount of air I got from each wheel cylinder that I didn't get with the other methods. Not sure why 1/2 strokes work, but it did. Brake pedal is higher and much firmer now but I buggered up the bleeder on the left rear and don't want to tighten it too tight until I replace it. At that time I will bleed one more round and then test drive. Another update will follow.

I also did a toe in adjustment per the manuals direction and it worked out well too. I use manuals all the time for unknown procedures and tasks, but that brake bleeding procedure wasn't something I thought I needed to read up on. Wrong! Note to self....READ THE MANUAL!

[JD luxury liner]

Good job, sir.  Nice car

JD luxury liner

[oldodge41]

Finally got a decent drive in with the new master cylinder and other assorted parts. Everything working well. I am happy with the results of my winter endeavors.

[ptwothree]

I think I would find a nice deserted road someplace and take it up to 30 mph or so and stomp the hell out of the brakes....over and over.  Then get under it and see if there are any cracks on the welds. Better to find out now than later.

 

Btw, what welder are you using??     Just one shade tree guy to another..........

[dale]

I think Id get a pro welder to go over those welds.  

[48ply1stcar]

Oldodge41, So it's been almost a year.  How did your bracket hold up over the summer.  Is there any thing you would do differently.

I want to convince my brother-in-law to make one of these brackets.   Also, I want to use a chevy master cylinder with a remote fill.

 

Any suggestions, recommendations, or rude comments that would help.

[oldodge41]

Sorry for not updating last summer, but there wasn't really any new developments. The bracket held up fine. The whole system worked as planned, but I took it off and reinstalled my stock type MC. I was going to cut out pieces for another one and have everything professionally welded, but decided to go a different route when I do. I am thinking about a two piece setup. One piece would be strictly a pedal mount, and the other a MC mount or possibly a pedal mount and a hanging brake pedal with firewall mounted master cylinder. I hate having to pull the floor up to check fluid levels. A remote fill like you propose would definitely be an advantage. I have made no progress on that idea yet, still thinking. I beat the brake system pretty hard trying to bust that thing while it was on the car but the bracket I removed showed no signs of flex, cracking, failed welds or other damage of any kind, but the seeds of doubt had been placed and I would never forgive myself if my part failed and injured another person. 

48ply1stcar I would say go for it. I would advise you to watch for the dimension from the frame to the center of your MC to insure proper brake pedal placement. I am not familiar with Chevy parts, but a master cylinder isn't what I would consider brand specific. It is all about dimensions, bore sizes, pedal travel and personal preference. 

 

 

[48ply1stcar]

The MC I am considering fits chevys, has ports on both sides, and would be compatible with the remote fill unit above.  If not a set-up like yours I would use a set-up I have seen where the new master cylinder is mounted behind the original MC and the rod is extended though the MC. 

[etzmolch]

I used this MC with bracket I made myself.

http://www.wilwood.com/MasterCylinders/MasterCylinderProd.aspx?itemno=260-7563

Not tried yet beacuse of winter here and some isues with the rear end....

 

Andre