i've been working on my 50 mford f1 for a bit under a yr and a half now. today was finally the day it would be able to leave the garage under it's own power, very exciting! there were only a few problems that need to be adressed. However the one i am most concerned about is the fact that the brakes pretty much didn't work at all! First off, the truck has a malibu front clip with power discs up front, drums in the rear and a willwood proportioning valve right before the rear brake line t's off to each wheel. the problem i was having is the brakes would hardly work when the truck was idleing, i would have to pump them and even then they woudln't build good pressure. And it got even worse when the truck got up in the rpm's. I wouldn't have taken it out at all but like i mentioned, they felt crappy at idle, but at least good enough to go around the block. Anyway, i pulled the front wheel off to fix something unrelated, but i noticed the rotor was very hard to spin, as if the caliper was sticking or something. Im sitting here scratching my head because the master cylinder is new (i bench bled it on the truck before installing the lines), brake lines are new and unclogged. the only thing i could think of is if the calipers up front are bad or something is leaking somewhere, i'm not sure. any help would be great guys, this thing is really close!
Are you sure the pedal is releasing the master all the way? Did you install residual valves? Some master cylinders had them built in,so you might have too much residual pressure... How much cam? Maybe the booster isn't working for you.
double check that the bleeder screws are are the top, you may have switched the right and left calipers . If the bleeder is low you will never get the air out, since the lines are new, i would gravity bleed the whole system, thats alot of air in a brand new system. It is also possible that you have a cocked piston in the caliper that is stuck, square it up in the cylinder if nessasary. You may have over extended it buring the build ( hitting the brake pedal without pads in the calipers ) Just trouble shooting, these are comman issuses truck looks good , I hope this helps MrC
Sleep on it..then re-trace your steps. Walking away from it sometimes will clear things up for you, I've found. Do a search on here also, lots of threads on brake issues. Good luck.
thanks for the responces guys. As for residual valves, i was under the assumption that they wouldn't be needed for my setup. i may be wrong though. i could try to gravity bleed the whole system just to make sure there isn't any air. one thing i should note is the brakes worked almost identically without the motor running at all, so i think the problem isn't just with the brake booster
by the way, the cam is an edelbrock performer (sbc by the way) so im sure it's not too agressive, i don't remember the specs off the top of my head but i do know it's not a radical cam by any means
Are you sure the booster pushrod is the right length? I had a similar issue with my '42 Chevy with a Nova clip and I had to get an adjustable pushrod from the junkyard.
HARD pedal or soft? If the brakes work the same with or without the engine running, I'd say that points TO a booster problem, no?
let me re-phrase that, it does the same thing only much easier because of the power brakes, does that make more scence the pedal pushes really quick until about 3/4 pressed then gets hard but bleeds down fairly quick
well i guess you could say you're right. i found a small leak in one of the fittings from the brake going to the proportioning valve. ugh this thing won't stop leaking though, i took it apart, cut it back and re-flared it twice...still leaked. went to the parts store and bought a piece off the shelf that was the exact size i needed (to prevent me from needing to flare anything) STILL LEAKS! i was sure to not over-tighten it, just fairly snug, then when i noticed it was leaking, i snugged it a bit more, then a bit more...etc the only thing i can think to do now would be to replace the fitting, which i will do, but when it was apart i took a good look at it and nothing looked out of the ordinary. heres a picture of what im talking about, the sharpie cap points to the fitting that is leaking (where the brake line goes in) shit, wrong picture haha thats what my dog did to his bed when i got home from work... hold on
I think you had an upload malfunction. all I see is a kitchen that looks like a dog destroyed it. Sounds like a bad master. some of the reman'd ones are junk right out of the box. A friend of mine had to get three different ones before he hit a good one. *edit* you uploaded another pic while I was typing. Stupid question time - the fitting you are pointing at - does it have the proper seat for the flared end of the brake line to seat against? I would try to eliminate the double fittings if possible & get one that will work for you. one less connection is one less place it can leak.
I'll go through a list of common problems I see at work with rods so don't take offense to any of this! LOL BENCH BLEED THE MASTER CYLINDER? LEAKY FITTING PIPE THREAD TO INV. FLARE? UPSIDE DOWN CALIPERS? PROPERLY BLED LINES? REAR HARDWARE INSTALLED CORRECTLY? RESIDUAL VALVES INSTALLED IF MASTER IS UNDER THE FLOOR? PUSH ROD LENGTH PROPER? BOOSTER ROD ADJUSTED CORRECTLY? PROPER PEDAL GEOMETRY? Ok these are just a list of common mistakes I see everyday... now you say residual valves arent needed?? is your master on the firewall or mounted on the frame?
is there any way to simplify this? lol is was a pain just to get that to work. the fitting that the brake line goes into IS inverted flare though. so i do have the proper fitting configuration where the leak is
Looks like 1/4" line to the rear a simple 1/4" to 1/8"NPT fitting and you can remove the one in the prop valve and have one fitting there
ok, double checked the said fitting. i may have found something, even though the fitting looks like an inverted flare fitting, it doesn't exactly look like it would seal correctly. almost as if it's an inverted flare fitting for something other then a double flare brake line. this may be a stupid question, but is there a good place to order some oddball brake fittings. i'd like to get something i could just take straight into the proportioning valve from my brake line to eliminate at least one fitting no it is firewall mounted. the brake pedal is correct with the master cylinder. i dont know what you mean though about having the rod adjusted correctly on the booster, to be honest i had no idea there was even any adjustment
Yeah from the booster to the master should have a 5/16" nut that you can adjust that plunger length also is the master a power or manual unit?? the pistons in a manual master are deeper
you want it to just make contact with the plunger in the master, a very slight preload isnt a bad thing and as for the fitting Carquest or Napa or O'reilly should have it in the edelman line
Id say adjust it out a lil and give it a try after fixing the leak, its free and somewhat easy to do if it doesnt work or was setup properly then start looking elsewhere for the headache!
I stated that wrong (putting kid to bed at the time) but you have way too many fittings there, regardless of type. More connections means more places to leak. Also, I learned from an old SR71 Mech to use a small dab of antisieze on most fittings, works better than pipe dope and fucking crap teflon tape
awesome guys, thanks for the support. im leaving for florida this next week so hopefully i can get these brakes working and take it for another spin before i leave!
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