|
 Investigation of a 1955 Mopar 1639 515 Power Brake Pedal SystemJump to page : 1 Now viewing page 1 [50 messages per page] | View previous thread :: View next thread |
| Forward Look Technical Discussions -> Brakes, Wheels and Tires | Message format |
56D500boy |
| ||
Expert 5K+ Posts: 9898      Location: Lower Mainland BC | . I decided in my stupidity/boredom/Covid fever (not really) to embark on another project for my 1956 Dodge Custom Royal D500. I really want to install a dual drum/drum Brake Master Cylinder but because I have the bellows-style Power Brakes, the master cylinder is very low on the fire wall. This means installing a dual MC will result in conflicts with the D500's 315 wide dual-rocker valve cover (as in difficult/impossible access to spark plugs, etc.) It's bad enough even with the single master, as shown here: Adding a dual master that low would be worse, as mocked-up here: Two years ago, I found this set-up on a 55 Desoto (below). I was using a newer PB booster and a dual master. I should have bought it but I was too stupid and when I went back to buy it, it was gone. This: Then more recently, I spotted this photo in a 56 Dodge wagon for sale advert: In both cases, the booster and the MC are sitting high on the firewall, not low like mine. After a brief bit of investigation, I realized that both of these conversions were based on the 1955 Mopar (one year only) 1639 515 Kelsey Hayes power brake system that had the booster and MC up high, as shown (sort of) below: This illustration from the 55-58 Mopar Parts Catalog shows the 1955 Mopar 1639 515 system compared to the manual brake system and the later 1637 814 system that I currently have. On that basis, I decided to seek out and purchase a 1955 Power Brake Pedal system. My first stop was to contact John F. at Big M auto in Williams, CA. John had a system from a 1955 Chrysler and after I determined that all 1955 Mopars (Chryslers, Desotos, Dodges and Plymouths) that had Power Brakes used the same exact parts, I committed to buying the power brake pedal assembly from John's 55 Chrysler. Getting it here (Canada) is not as easy or cheap as it was before Covid but once we committed and I paid John, I had it in my hands within a week. (Thanks John, and Doug at Border Mailboxes in Blaine WA). When I got the pedal assembly, it was a "bit" rusty (just surface rust) so before I did anything, I soaked the assembly in EvapoRust for a day and a half. Cleaned up real good. Then I disassembled it (I had to resoak a few of the parts once it was apart) and started playing with it. First thing was to mock up the pedal assembly using a 3/4" thick piece of MDF that I had laying around, tracing the shape of the pedal bracket and locating and drilling holes for the main pedal attachment bolts. Once that was done and I had the pedal, the links and "lever" assembled, I tested the position of the pedal and the lever (where the PB booster push rod will connect to) in three positions. The positions closely mimicked the actual pedal movement from full up at the stop bumper (which is missing) and the floor of the footwell (I based this on the information for the 1637 814 system that I currently have). Turns out, for a pedal movement of about 4.5", the lever moves half that distance, i.e. about 2.25". The plane that the clevis hole in the lever follows is fairly close to the center line of the Power Brake Booster (and MC). I am not sure what the throw of the MC will be but I think that it will be in the 1.25" to 1.5" range, i.e. well under the 2.25" that came out during my investigations. Some info that I gathered and photos that I took during this investigation (so far). One of the interesting bits is the brake pedal bracket 1559 745 was the same for all 1955 Mopars, manual or power brakes. This bracket was also used as the 1956 Manual brake bracket. Learn something new everyday. Edited by 56D500boy 2020-12-22 8:15 PM (55ChryslerPowerUnit1639515Diagram.jpg) (55ChryslerPowerBrakeDiagrams_2.jpg) (55ChryslerPowerBrakeDiagrams_1.jpg) (55ChryslerPowerBrakeDiagrams_3.jpg) (PedalBracketDetails_Trimmed_Annotated.jpg) (55ChryslerPBPedalAssembly_LeftSide.jpg) (55ChryslerPBPedalAssembly_FireWallSide.jpg) (1559745_55-56BrakeBracketListing.jpg) (55ChryslerPowerBrakePedalAssembly_DisassembledAfterDeRusting_Annotated.jpg) (55ChryslerPowerBrakePedalArrangement_MovementMeasurements_Position1.jpg) (55ChryslerPowerBrakePedalArrangement_MovementMeasurements.jpg) (55ChryslerPowerBrakePedalArrangement_MovementMeasurements_ShowingPlaneOfClevisMovement.jpg) (55ChryslerPowerBrakePedalArrangement_MovementMeasurements_ShowingPlaneOfClevisMovement_WithoutBracket.jpg) Attachments ----------------  55ChryslerPowerUnit1639515Diagram.jpg (79KB - 327 downloads) 55ChryslerPowerBrakeDiagrams_2.jpg (203KB - 326 downloads) 55ChryslerPowerBrakeDiagrams_1.jpg (90KB - 312 downloads) 55ChryslerPowerBrakeDiagrams_3.jpg (57KB - 308 downloads) PedalBracketDetails_Trimmed_Annotated.jpg (184KB - 302 downloads) 55ChryslerPBPedalAssembly_LeftSide.jpg (183KB - 320 downloads) 55ChryslerPBPedalAssembly_FireWallSide.jpg (120KB - 318 downloads) 1559745_55-56BrakeBracketListing.jpg (188KB - 315 downloads) 55ChryslerPowerBrakePedalAssembly_DisassembledAfterDeRusting_Annotated.jpg (168KB - 304 downloads) 55ChryslerPowerBrakePedalArrangement_MovementMeasurements_Position1.jpg (88KB - 319 downloads) 55ChryslerPowerBrakePedalArrangement_MovementMeasurements.jpg (174KB - 315 downloads) 55ChryslerPowerBrakePedalArrangement_MovementMeasurements_ShowingPlaneOfClevisMovement.jpg (112KB - 311 downloads) 55ChryslerPowerBrakePedalArrangement_MovementMeasurements_ShowingPlaneOfClevisMovement_WithoutBracket.jpg (115KB - 310 downloads) | ||
| |||
| ronbo97 |
| ||
Expert Posts: 4036 Location: Connecticut | |||
| |||
| 56D500boy |
| ||
Expert 5K+ Posts: 9898 Location: Lower Mainland BC | ronbo97 - 2020-12-22 6:15 PM You need to get a thorough understanding as to how the 1955 Bendix (not Kelsey Hayes) system works. If you're planning to use any currently available dual m/c with the original Bendix booster, you may be disappointed. Regardless of who made the 1955 Mopar Power Brake booster and master cylinder system, after reading through the 10 plus pages of service instructions for the combined booster and MC unit in the 1955 Chrysler Factory Service Manual (FSM) some time ago, there was no way in H*LL that I was going down that path way. But I did like the peddle system and the high mounting position of the booster (and MC)).  I plan on using a booster from either a 1968 Chrysler or a 1975 Chrysler (leaning towards the 1975 booster at the moment). This will be the topic of a separate thread, starting soon (after I get the booster from Santa). As for Kelsey-Hayes or Bendix, I presume that I thought it was Kelsey-Hayes because of many old threads on this forum and these: https://www.moparmall.com/1955-MoPar-Brake-Booster-Master-Cylinder-U... https://www.parts123.com/parts123/yb.dll?parta~dyndetail~Z5Z5Z500010... https://www.ebay.com/itm/1955-Chrysler-DeSoto-Dodge-NOS-MoPar-Imperi... "Re-manufactured Kelsey-Hayes Vac-Draulic power brake booster and master cylinder assembly for 1955 Plymouth - Dodge - DeSoto - Chrysler - Imperial. For the 1955 model year, the power brake booster and master cylinder were integrated into one unit and serviced as an assembly. Although this configuration proved to be a reliable design, Chrysler Corp only used it for one year. Original equipment p/n 1639515"   Edited by 56D500boy 2020-12-23 2:52 AM | ||
| |||
| Stroller |
| ||
Extreme Veteran Posts: 371 | |||
| |||
| 56D500boy |
| ||
Expert 5K+ Posts: 9898 Location: Lower Mainland BC | . Finally, this AM, I found a diagram of the 1955 Power brake system showing the pedal, booster and master cylinder. It helps explain/confirm a few things (to/for me): Edited by 56D500boy 2020-12-30 8:19 PM | ||
| |||
| Powerflite |
| ||
Expert 5K+ Posts: 9649 Location: So. Cal | Dave, I measured the pedal ratio for this setup and found the same as you, that you get a 2:1 ratio in movement. http://www.forwardlook.net/forums/forums/thread-view.asp?tid=77701 That's pretty lousy. Most power brake pedals are setup for around 4.5:1. You noticed that you have more movement available than what you need. Even though the master cylinder total stroke is 1.5", you practically never need to use that amount. Anyway, I plan to use this setup on my yellow '56 Fury, but I am going to lengthen the pedal arm out by 1.5", keeping the pedal at the stock position. Just move the pivot up higher. Then I will move the pivot arm attachment to the fulcrum up by the same amount, 1.5". Doing this will increase the pedal ratio up to 5:1. More like what the '78 booster is expecting to see and should make it easier to apply the brakes on it. If you think 5:1 ratio is too much, moving those by 1.25" instead will result in 4.45:1 ratio. (55ChryslerPowerBrakeMods.jpg) Attachments ---------------- 55ChryslerPowerBrakeMods.jpg (90KB - 105 downloads) | ||
| |||
| Jump to page : 1 Now viewing page 1 [50 messages per page] |
| Search this forum Printer friendly version E-mail a link to this thread |
| (Delete all cookies set by this site) | |
