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So I did a little checking. I started by hitting the brakes when the truck was cold, then starting it, and trying again. The pedal feels the same in both situations. I checked for vacuum at the booster, and it has it going in (im not sure how much, Im going to get a gauge), and there is a valve that is working on the booster, so the booster is seeing at least some vacuum. I moved the vacuum hose to another port on the manifold, and even replaced the hose with a better, stiffer hose to eliminate the possibility of it collapsing under vacuum, which I havent seen, but just in case. Still works the same. Then it occured to me, they feel like manual brakes. It feels like the pedal on the F100, which is manual. Again, the truck stops, but it wont lock up a wheel.
Im going to get a vacuum gauge and see what its making. The internet says it should be 18" minimum. Then Ill go from there. So far, I think my booster isnt working. Its either undersized, or Im not making enough vacuum. We will see.
If you run the engine, Shut it off then remove the check valve from the grommet you should hear the vacuum sound. If you don't it's not getting or holding vacuum. Another thing you can try is remove the check valve while it's running and see if you are getting vac from the check valve(going in to the booster).
So I dug into the brakes today, and figured out the issue. I have been a victim of getting what I paid for. Time and time again I learn the hard lesson of buying cheap parts from vendors who dont care about you, your project or your safety.
So, the master cylinder has a casting number of 227161, making it a 1" bore MC for a 64-73 mustang, and it says it is good for disc/drum setups. The booster is a mystery. I bought these as a set from Pirate Jack, specifically for a 67 dodge d100, allegedly. Remember the rod that goes between them was too short, and never would have worked. I had removed the MC and the booster from the truck, and had them on the table. I noticed there was no gasket between them, and the mounting flange had surface rust on it, meaning it was not sealed. As I was reading up on it, a person asked if there was a gasket between the MC and the booster, and I found a that post said "No, the MC is sealed and the booster is sealed, if either of them leaks replace them." Then it dawned on me, the booster is under vacuum, and the MC is under pressure, they have to be separated from each other. That seems simple, but if the seal on the booster wasnt holding its vacuum, then the vacuum would come right out. Also there is a chance, if its sealed there, that the vacuum could draw fluid through the back of the MC, and ruin the booster, which I have had happen on a car before.
So, I flipped the booster over, and pushed on the brake pedal rod, and the seal just pushed out. Its made to be held in place by the MC. but I noticed there is a depth difference between them that wont alow that to happen. The flange on the MC is 9/16" deep, but the booster has a hole depth of 31/32" without the gasket. If my basic math hasnt left me, thats a difference of 13/32". So, I stacked a few large o-rings and a grommet in between them and put it all back together for a test, and it worked. I know this is not a permanent fix, but its working pretty good. Ill have to make a spacer to hold the gasket in place, or buy another booster.
I cant count how many times buying a cheap part has cost me more than I paid for it. Im going to just start ignoring the first 3 pages of a google search, and maybe the Pirate Jacks and the Uncle Jimmys wont be on the 4th page, and I can start to get some good parts. You expect it from Rock Auto, but now everyone is selling cheap garbage. No seal between them. And there isnt supposed to be one. Booster hole is 31/32" deep without the gasket. Master cylinder flange is 9/32" tall. Thats a difference of 13/32". It would have never worked. The gasket pushes right out if it isnt held in place with the MC.
Yeah, part quality is taken a major nosedive of late.... It's depressing. Used to be able to get High Quality parts, that were actually made right here in the Good Ol' US of A, not the case any more.....
I have been working on the truck, and doing a few things. Life has thrown a few curve ***** at us. I have changed jobs, and sold the Ford to reduce the strain of getting 2 classic trucks going. I spent most of last year putting a 5 speed in it. Got it running, and just didnt want to do any more. My heart isnt in that truck. My wife and I talked and I want to work on my Charger (its an 07 RT). So we decided to sell the ford, and work on Isaacs D100, and my car instead.
I got a good deal on a crate remanufactured 5.7 for my car, so I jumped on it. Its in the basement awaiting a cam. When I put it in, itll get a complete exhaust, and a tune. Maybe some other stuff. I just put head gaskets on the engine in the car this weekend. Life giving me lemons and all...
Anyway, out of stubbornness, I decided I wanted to get Isaacs truck to the Bristol leg of the power tour this year. It will be coming though our area in early June, just a week or two away. I knew I couldnt make the long haul, but surely I could get it together to make it to Bristol. Right? Well, no actually. While I was driving it yesterday, the longest continuous outing I have had in it (probably about 10 miles) I noticed the oil pressure is staying at 20psi or less. At idle it drops to about 12-15. When I run it out to about 2500-3000 rpms, it stays around 20 psi. Im no 5.2 magnum expert, but that seems very low to me. I also heard a bunch of valve chattering. The rest of the truck seems to be going good so far.
Ill be working on a solution for this engine next I guess. If (probably when) it comes out, we are fixing a bunch of other issues. The steering column, the heater, it needs some sound/heat insulation on the floor, wheel studs...There are tons of things to do.
