I've got a 69 f250 cmpr special with the 390 in it. It's got disc brakes in ftont and drum in the rear. When I step on the brake pedal it almost feels like no power brakes... It takes a good bit of leg power to push. The truck stops quite well for being a big ol beast. And I can't seem to get it to idle low enough. Don't have exact rpm numbers as I haven't installed the tach yet. But let's just say once it's warmed up I've got to keep the choke cable at least 1/4 of the way out to get it to idle low enough I can put it in gear (has the a.t. not manual) without feeling like I'm gonna do damage to the trans. And you can hear it's idling way too high in p/n. This is the first ford I've ever owned so any ideas/help is welcomed. Thanx in advance.

 

Yeah first thing is you should have a manual that covers your truck to do the simplest things like what your asking.

How to do the carb setting for the idle & air/fuel jets screws on the carb.

How to do a tune ups.

If "Idle is up to high back out the carb idle screw" at carb linkage.

A vacuum leak will also cause it to high idle also.

A bad Distributor vacuum hose or vacuum advance can cause a high idle.
orich

 

The vacuum lines have all been replaced with new ones... And my wife got this for me as a project truck... That being said I don't have The original owners manual... I'm just trying to get this beast to run right.

 

Original owners and shop manuals are available from faxonautolit.com (store located in Riverside CA .. open Monday/Saturday).

1964/72 Ford Truck Parts Catalog available on a C/D from hipoparts.com

In case you're unaware, dual piston caliper front disc brakes were an option for 1968/72 F250 2WD's and F350's. With front discs, the F250's rear drum brakes are 12" x 2 1/2."

 

Book manuals
1973-79 Haynes pickup& Broncos cover most the stuff. The owners manuals can also be found on ebay and at times on Amazon.com

Tranny vac line behind carb to module leaking or Brake vacuum line or booster sucking air.

Orich

 

Sounds to me that your brake booster is bad. 1st, brakes hard to push. 2nd,when the rubber diaphragm ruptures in it then it is a major vacuum leak. To test this theory take the booster's vacuum line back off and plug it. Start the engine. Idle will be a lot better. What usually ruins the booster is brake fluid seeping out of the back of the MC and in to it. Before buying a booster (if I am correct) leave the lines on the MC but gently remove it from the booster. Pull it just far enough forward where you can get your finger in the back of the MC to feel for fluid that's not supposed to be there. You may have to buy both.

 

I've already had to replace the old master cylinder. It was nasty as all hell on the inside. I didn't notice any fluid in the booster. But of course I wasn't looking for it then. Thanx for the responses and I'll try both of your ideas. I'll update when I've got more info. Thanx again.

 

Also check the vacuum advance on the distributor for a leak.

 

O.k.... Update to the high idle vacuum leak... 1. Bad power brake booster check valve, 2. Bad pcv valve. Running much better now. Of course I had to completely reset to initial settings the high idle,the idle and the idle mixture screws and start over tuning the beast. But at least it finally runs right and the brakes don't take so much pressure on the pedal to stop! Thanx for all the comments and help.

 

No Problem. THANKS for the info on the fix and closure!