View Full Version : Possible Vacuum Leak?

04-28-2014, 05:33 AM
So i have very recently aquired an 89 Thunderbird SuperCoupe

Love the car, but it has no Power brakes.
The guy i got it from said it was because of a Vacuum Leak.
Does this sound remotly plausible?

It does have another intermittent symptom that leads me to believe it is a possibility.
If you sit with the brakes on for an extended period of time, Ie long red light, the car startes to idle weird. and the boost gage fluctuates from the standard 20-21 mmhg vacuum at idle to ~10 mmhg.
It also causes a fluttery idle which seems to dip slightly into boost, which is a little weird to me, but may be normal.

It also seems to CONSTANTLY run rich.
I get clouds behind me when i take off, but it could also be a myriad of other things. Could be burning oil, could be a BHG (coolant reserviour has copper flaking dried in it. HG/Radiator repair stuff)

The car also has no power steering, but that is a blown line. Assumingly unrelated, but cant hurt to mention it.

04-28-2014, 05:36 AM
Most brake boosters are vacuum, it does make sense.

04-28-2014, 07:13 AM
The brake booster is indeed vacuum operated so a leak in the line will definitely impact the amount of force you have to use. However this should be a very easy repair (probably a broken hose, just replace it).
If there is a cloud behind you, what color is it? What does it smell like? You'd know if you were burning oil because your oil level will constantly be dropping (assuming you don't have leaks elsewhere).
Also if the only thing wrong with your power steering is indeed the high pressure line and not the pump, it's about 50 bucks to replace it. Worth it IMO.

04-28-2014, 11:09 PM
Disconnect the booster line and cap it. See what happens.

04-30-2014, 05:16 AM
So doing more research, i apperently have an electronic Brake booster.


This is going to be a giant pain in the dick.

05-06-2014, 07:02 AM
never was able to get anything fixed. blew a headgasket the day after my birthday... ordered a top end gasket kit and ARP studs just now.
i know what im doing in a couple weeks once i find a place to live...

05-07-2014, 02:26 AM
Damn Aaron, that is the most messed up brake system I've ever seen. Your entire brake system, master cylinder, power brake booster, valving and ABS system are all built into that damn module that sits where the power brake booster normally sits.

Before you go too far into the head gasket change, I'd check into what your options are for fixing the brakes. IF there is no retro fit to do away with that monstrosity, check right away to see how much it is going to cost you to get a replacement. It doesn't sound like this was used on too many cars and finding a GOOD used one maybe a problem. There maybe a way to do away with the ABS like on the 5th gen Celicas with ABS. When your car was built, ABS was still primarily an option. You maybe able to use the brake booster from a non-SC Thunderbird along with the proportioning valve. It would be worth checking. From what I scanned over in that article, it looks like this in not an uncommon problem. If that actuator is expense as it looks like it might be, I would be willing to be that someone in the SC community has found away to do away with it. If you can't and the only way to get one is to sell your first born, it might be better to ditch the car.