Vaccum Leak?...messing up my brakes...88 people also come in.

[TrophyHead]

Can a vaccum leak make my brake pedal go soft all the time? I pressure bleeded the brake sytem and my pedal is still not acting right. I just had the upper intake off and I replaced the vaccum lines that looked bad. Trying to figure out what lines to look at? I also bench bleed my MC which is brand new. Thinking about going to manual brakes...though I havent heard to much about this.

Also for you guys with 88's what kind of repair manual do you use? I have a Chilton 1979-88 and the whole book is mostly about carbs and 4 cylinders. Not much information about 5.0's in there. I was thinking about buying the 89-93 Chilton book. Isnt 88 just about the same as a 89-up except for mass-air? Do they have the same vaccum lines and emissons stuff? Just looking for a more detailed technical 5.0 book. Maybe a Ford 1988 service manual would be better?

Thanks guys.

 

[ALMOST STOCK]

Yes if you have a vacuum leak your brake pedal can feel completely different.
Your best bet would be to buy the 88 Ford Shop Manual if you can find one.

 

[RsStanG1987]

I have the 86-93 5.0 haynes maunual its great. I had a vacum leak because i missed one putting my upper back on. The car would idle high and cause my tranny to shift at weird points. It also made the brakes work like ****. Listen for a whistling or air leaking noise and go from there.

 

[HISSIN50]

Can a vaccum leak make my brake pedal go soft all the time?

Thanks guys.

i might be off base here, but in my experience when there is insufficient vac at the booster, the brake pedal is very stiff (like if you have braked while the car was not running).

i would still wonder about air in the lines. it can be a bear to get out. make sure nothing is leaking (wheel cylinders can be deceptive). and DONT drive it with compromised brakes!

good luck.

 

[giddyup306]

First thing I'd do is bleed the brakes. Fill up the master cylinder with brake fluid. Get a friend to hold down the brake pedal while you losen up the bleeder screw and using the proper tube with an old soda bottle to catch the excess. I beleve it is a 7/16" screw and you will need a line wrench to do so.

 

[TrophyHead]

OK guys I'm an idiot...My 73mm calipers where on the wrong sides. I guess air was bubbling up in the bleeder screw or something. It's good to go now. I feel like a dumbass. lol

 

[stanatic]

please help me because i don't know much about vacuum leaks and such. you guys say a vacuum leak can cause the brake pedal to feel stiff. my brake pedal feels very stiff. now, i'm also having problems with my a/c. it only blows air from the top vent. i've learned that this is from a vacuum leak. is this the same type of vacuum leak you guys are talking about?

 

[Duro5341]

Sounds like you definetly have a vacume leak..........
The HVAC controls also run off a vacume.

Now check that all the vacume lines are connected, especially the one going to the bootser. If there all connected get a can of Carb Cleaner spray, and start spraying all around the engine, and listen. When the carb cleaner gets sucked into the vacume leak it will cause the engine to surge. This can take some time........but you'll find it

When the engine surges go back to where you just where, and spray again. Even a small crack in the lines, will cause a vacume leak...........this is why it is such a pain to find, and so simple to fix.

A vacume leak will also cause the engine to idle really rough, kinda sounding like it has a really big cam.

Have fun...........Just my 2 cents
Duro

 

[1EVIL88VERT]

the problem with the a/c sounds like it is the small vacume line the runs across the firewall from the large vacume tree on driver side to a vacume T on the passenger side. It seems to break on every mustang sooner or later.

 

[jrichker]

See http://www.veryuseful.com/mustang/tech/engine/ for vacuum line diagrams

 

[stanatic]

k, so i took it to my "mechanic" and he quickly ran a fresh vacuum line across the firewall like someone described. it goes from the tree to some point on the other side. i would have to look at it again to tell you where. from what he said, he bypassed the booster as a quick fix because that line was busted and would have required removing the tire or something. well, the air controls now work, air blows out the front vents. but the pedal still feels the same. i wish i would have seen this diagram sooner. i was actually looking for something like this! now i see why my cruise control doesn't work either! so apparently my vacuum leaks are causing all kinds of trouble for me.

i have the haynes 79-93 manual, but i didn't find anything about vacuums in there so i'm very grateful for the diagram that was posted. thank you jrichker!! i'm looking at the site you posted and i think the 88 gt diagram resembles my car better, cuz that vacuum distribution block looks very familiar. how simple would you say it is to just replace the vacuum lines? i don't mind buying 10 or how many feet of vacuum line i'll need and just replace them all. has anyone ever done this before? i think i'd rather do that than mess around with carb cleaner to try and find the leak. anyone have any advice to give me on this? thank you!!