Sam Buchanan

I don't really understand why the new MC didn't work either. First thought it was a bleeding issue but after running a quart or so of fluid through it never could get a pedal. The MC appeared to be pumping properly.....sort of a mystery. I even tried the front brakes without the residual valve but that didn't help. I suspect the problem is something simple but I couldn't nail it down. Since I have all the mechanicals done I may try again with a different cylinder when I feel energetic enough.... I cut a hole in the floor for access to the new MC. It would have required a cover with a slight dome shape but is mostly under the front edge of the seat so wouldn't be a problem. The geometry of the pushrod is such that it doesn't touch the old cylinder even at full travel.

Well....this is not the update I wanted to make. In spite of many attempts to bleed the brakes I was unable to get a satisfactory (hardly any) pedal with the dual-chamber master cylinder. I used to tell my science students that because an experiment didn't have the anticipated result that there was still knowledge to be gained. I suspect the cylinder I used didn't have sufficient displacement. It is a 1" bore and maybe a larger bore cylinder is needed since the standard cylinder is 1 1/8" bore. I reasoned that 1" was sufficient since each chamber was only pushing wheel cylinders on one end of the car but that must be faulty reasoning. However, mechanically the mod worked flawlessly, the bracket and pushrod were an excellent setup. All that is needed is a master cylinder that is compatible with the P15 wheel cylinders. I wimped out and installed a new standard cylinder which bled as expected. I'll ponder this some more and may revisit the mod at a later date.

This tool has been improved and updated and can be found in this thread. Like many newbies to the P15, I'm finding the brakes to be the most frustrating aspect of an otherwise simple vehicle. The absence of a factory adjustment tool certainly adds to the uncertainty of setting up the brakes in addition to not having prior experience with the Lockheed brakes. I filed flats on the ends of the anchor bolts so they can be adjusted with the drums in place but I just wasn't confident the shoes were concentric with the drums. The tool below is one I fabricated from scrap material in the shop and it provided visual confirmation that the shoe adjustment was close to what it needed to be. This is not an original idea and many of you may already have something similar, just want to toss this out for those who are struggling with brake adjustment. The tool is just a length of .875"x.059" steel tube with some 1/4" all-thread welded to it. A short length of aluminum angle forms a pointer than can be adjusted via the nuts on the all-thread. The tube is a close fit on the 3/4" spindle. With the drum in place one minor adjustment cam was set so the toe of the shoe barely dragged. The drum was removed and the pointer on the tool adjusted so it barely touched the toe of that shoe which is a close approximation of the ID of the drum. It is then just a matter of sweeping the tool over the shoes to adjust them so they are concentric to the drum. It turns out the method I had used to adjust the anchors and cams with the drums in place was pretty close but this added visual confirmation. I don't have the rear brakes opened at the moment so can't recall if the same steel tube will work on the axle. The tool could also be built by welding the all-thread to a spare axle nut.

I recently added directional signals to my '48 P15 with the same switch. Be sure the flasher and the Signal Stat have excellent grounds. Do the brake lights still function? If not recheck the brake switch wiring and the connection you made at the switch. Stay with it, you'll figure it out.

When the '48 Special Deluxe sedan followed me home one of the first mods that came to mind was changing the standard master cylinder to a dual-chamber cylinder. Since the time in my very distant youth when my 1963 VW Beetle rolled into an intersection when a brake line let go I have been very wary of single-chamber master cylinders. I first checked with ECI to see if their master cylinder retro-kit was suitable for drum/drum brakes and was informed it was only for disks/drums. My hours spent researching the forum archives uncovered a photo of a retro-fit that formed the inspiration for this conversion. I don't recall who posted the photo....but Thank You. I'm including some in-process photos and will update as the conversion is completed. If anyone sees any gotchas feel free to wave a red flag. Here is the retro-fit as it stands this evening: The new cylinder mounts behind the body of the old cylinder and is activated by a pushrod running from the brake pedal through the gutted old cylinder to the new cylinder. The pushrod was fabricated with a combination of 5/8" steel tube and the ends of the old pushrod: It seems the original pushrod components are not easily replaced so this will allow them to be put back in service if a standard cylinder is used at a later time. A 7/16-20 nut was welded to one end of the tube and a 7/16-20 bolt to the other. This allows the pushrod length to be adjusted for proper pedal free-play. Below is the new master cylinder bracket, it is 0.090" steel and through-bolted to the frame rail:

The saga continues......received a little bag of #12-24 filister-head screws today, rushed breathlessly out to the Plymouth to replace the carb bowl screws and.....no joy....turns out the screws need to be #12-28. Started looking and #12-28 screws like the ones in the carb are nearly unobtainable. There are a few socket-head and brass screws in this size but it seems this screw went out of style with '78's (records). One of the holes in the carb bowl is missing about 3/4 of its threads and that's why I wanted to find some slightly longer #12's. It looks like the best option if the rest of the threads pull is heli-coils with modern threads. This is the charm of old cars.

My recently returned-to-the-road '48 Special Deluxe is running a Carter P4259 6v electric pump mounted near the tank as the sole means of pushing fuel to the carb. So far the engine seems to be very happy with the pump without a regulator. There is now a block-off plate where the old fuel pump was mounted on the crankcase. I ran the 12v version of this pump for several years on my StalkerV6 kit car with a carb and it functioned perfectly. The pump is wired to the ignition switch but I may add an oil pressure switch to the circuit....or may not...kinda adverse to adding single-point-of-failure modes to the system. The pump runs all the time when the ignition is switched on. It is barely audible at idle but not when the car is going down the road.

Well.....I'm relieved see the finely honed craft of thread creep is alive and well on this forum! Glad I was able to provide grist for the creep mill and that the thread is being enjoyed to its fullest. Carry on.

Yes they are, used them many times for various ground and air projects. I'm sorta embarrassed about getting sidetracked on the metric thing, just wasn't expecting to find #12 screws that are so close to metric size. More educated now.

Yep, #12 is a bit odd now-a-days, can't recall ever using that size for anything. The carb screw mics 0.210" (5.5mm) which is correct for #12. What was confusing is the pitch was perfect in a M1.0 gauge which is a bit finer than -24, maybe -28?. Guess I need to run down a handful of #12's from somewhere, looks like the big auction site has a good selection. The photo is a comparison of #12 and #10. Thanks again!

First post after spending an unreal number of hours reading this forum after a '48 Special Deluxe sedan followed my home. Many thanks to all who contribute to the forum, a host of questions have been answered that has smoothed the process of putting the P15 back on the road. In the course of repairing the manifold heat control and the carb I have run across some metric threads. I intended to replace the fuel bowl screws (one online site sells #10 screws for this application) but the screws on my carb appear to be M5.5x1.0. The stop stud for the heat spring also appears to be metric. Are metric fasteners normal or do I have a Canadian or somethin' engine in my P15? The carb is stamped with D6G1 M7.