Vacuum Brake Converted-Hard Brake Pedal

[V6Turbo]

Just installed your vacuum brake kit. I now have hard brake pedal. Didn’t have it before the PM. Won't hold boost past 3 lbs..luckily my front brakes can hold on.

I bled the whole system including all 4 tires
Tapped the vacuum from the PVC Line.
No Vacuum leak as I could tell at least reading my BLM/INT #'s.
RPM Idle seems to be higher.

Please advise.

Thx in advance.

Virgil

 

[boostingbuick]

Sounds like a bad brake booster. Been there. We installed one on my bro's car and the pedal was very hard. Replaced the booster and then tested the seatbelts. He loves the vacume brakes over the powermaster pain in the butt.

 

[SNOWBIRD]

Your Vacume Source Is Not Sufficient (eliminate Pcv)

 

[V6Turbo]

Better response time...PM or Vacuum?

Maybe I am not used to the Vacuum Brake response.

Which has better response time...PM or Vacuum?

 

[jdpolzin]

The brakes should not be hard. There is a problem somewhere. Where did you buy your kit?

 

[V6Turbo]

The brakes should not be hard. There is a problem somewhere. Where did you buy your kit?

Hard Pedal maybe a relative term. Compared to the PM it seems harder to press OR the response time is slower. I have to press harder to stop and is not as quick. I also cannot lock the brakes.

I bought the kits from Red Regal T...used.

 

[jdpolzin]

Well, maybe he will chime in but it sounds to me like a bad booster. I know his kits are used parts but maybe he will refund you. The vac set up should pretty much work as the PowerMaster did. If you are trying to hold boost at the line, you have to build RPM's up in the motor then press the brake pedal. But, the holding power should be as the PM is if the booster is good. How long have you had this in you car? Good luck.

 

[V6Turbo]

Well, maybe he will chime in but it sounds to me like a bad booster. I know his kits are used parts but maybe he will refund you. The vac set up should pretty much work as the PowerMaster did. If you are trying to hold boost at the line, you have to build RPM's up in the motor then press the brake pedal. But, the holding power should be as the PM is if the booster is good. How long have you had this in you car? Good luck.

I just installed it yesterday. I just swapped out another booter from AZ today...same results. Also I cannot get the brakes to lock.

What about the master cylinder? What are the symptoms for a bad master cylinder?

 

[SNOWBIRD]

measure the amount of vacume you have at booster hose..should be about 16 to 18 in drive

 

[SNOWBIRD]

you mentioned you tapped into pcv line ...that is your problem... i am pretty sure..you are not getting max vacume ,,valve is a controled vacume leak

 

[BetMinesFaster]

+1-your problem is here...

you mentioned you tapped into pcv line ...that is your problem... i am pretty sure..you are not getting max vacume ,,valve is a controled vacume leak

You ever feel as if someone is not listening to what your saying??? LOl

I second this one, with the pcv on the same vaccum source you not going to have anywhere near enough vaccum to function properly...

 

[novaderrik]

i've run the brake booster off the same line as the PCV in other cars before and had the booster work just fine. i've even seen some oem cars done this way.
of course, i've never done it on a turbocharged car, but a car is a car and vacuum is vacuum. as long as the booster sees full vacuum at some point, the check valve will hold that same amount of vacuum until the brakes are applied- i've parked cars in the fall and had them still have vacuum in the booster 5 months later.
i'd be looking at the check valve to see if it isn't "leaking" the vacuum out (which is to say that it's actually letting air leak in)..

 

[V6Turbo]

Fixed-No More Hard Brake Pedal-But Still Low Boost Hold

Snowbird...

Thanks for the help. Just got it fixed. I tried another vacuum line instead of PCV as you suggested. I think the main problem is that I used a 5/8 inch hose instead of 11/32 inch on the PCV line. The fact that the PCV line has a tendency to spit out oil into the vacuum line did not help with the seal and easily came off.

I can now stop with confidence.

However, I still have 2 problems:

1. I still cannot hold boost pass 3#lbs on rear brakes.
2. The brake is not as responsive right after boost. It's a new check valve and it works.

Thx,

 

[chris718]

Does The Pedal Push Back At You During Boost ?

 

[TURBOPOWERED68]

Snowbird...

Thanks for the help. Just got it fixed. I tried another vacuum line instead of PCV as you suggested. I think the main problem is that I used a 5/8 inch hose instead of 11/32 inch on the PCV line. The fact that the PCV line has a tendency to spit out oil into the vacuum line did not help with the seal and easily came off.

I can now stop with confidence.

However, I still have 2 problems:

1. I still cannot hold boost pass 3#lbs on rear brakes.
2. The brake is not as responsive right after boost. It's a new check valve and it works.

Thx,

thats allways going to happen you have to learn how to drive your car all over again this is my biggest problem with these cars.

 

[John Larkin]

Try this test: Take cover off master cylinder, leave hood up, place lots of towels around master cylinder at least 18" & especially over fender, start car, press brake pedal hard and somewhat quickly, look between hood and cowl and watch for an upward spurt from the reservior. If it does anything more than basically sizzle bubbles on the surface of the fluid you need another master cylinder, preferably a brand new one.

 

[novaderrik]

wow.. every master cylinder i've ever had in every car i've owned has been bad, at least judging by the amount of fluid that flies everywhere when i push the brake pedal with the reservoir cap off. oddly enough, the only time i've ever had DOT 3 brake fluid NOT spray everywhere was when i had a bad master cylinder...

 

[John Larkin]

Some people are just unlucky.

 

[SNOWBIRD]

I Think Its Time For A Good Vacume Bleeding Of Complete Brake System.......a Set Of Soft Rear Brake Shoes ...2 7/8 In Brake Cylinders And Turn Or Deglaze 2 Rear Brake Drums.. Adjust And Road Test You Wont Believe The Difference It Should 7 Or 8 Lbs Of Boost On The Line

 

[V6Turbo]

Try this test: Take cover off master cylinder, leave hood up, place lots of towels around master cylinder at least 18" & especially over fender, start car, press brake pedal hard and somewhat quickly, look between hood and cowl and watch for an upward spurt from the reservior. If it does anything more than basically sizzle bubbles on the surface of the fluid you need another master cylinder, preferably a brand new one.

I am a bit confused...Should you mean if I DON'T get a big spurt or only sizzle bubbles it is bad?

I get big spurts and no bubbles..so my MC should be good. Please clarify.

thx, Virgil