Vacuum Brakes + Crane Roller 212/206 = No Brakes HELP

[KWIKR 1]

I'm just breaking in a new engine with a Crane Roller 212/206 . My vacuum brakes are fine just driving around town . But if I give the car a good blast when I go to brake there's nothing there . No power asist at all . Has anybody had this problem running vacuum brakes and one of these Crane Rollers ? Could it be a PCV problem (I'm aslo chasing a weird oil leak problem) ? and how can this problem be corrected ? I almost rear ended a car today because of it . Scary stuff . Please help, my wife drives this car often and I have to fix the problem . Thanks.

 

[Steve Wood]

How much vacuum at idle? If you have less than 12" at idle, the booster may not be storing enuf.

Is the check valve good in the booster?

 

[KWIKR 1]

I'll have to check vacuum at idle .What should the vacuum be with this cam ? Booster is less then a year old .Thanks.

 

[Steve Wood]

In gear, I would think it would be 12-14" when hot.

There is a check valve in the booster..its the piece of plastic that the hose connects to...it just pops into a grommet on the booster.

You should be able to suck on it, but not blow thru it

 

[cool 84]

Bad check valve?

Edit: I wrote this an hour ago and forgot to submit.

 

[KWIKR 1]

Check valve on brake booster is good . I just checked it .

 

[Steve Wood]

and what is the vacuum in gear at idle?

 

[KWIKR 1]

I'm waiting for my brother to drop off his gauge . I'll let you know .

 

[tazgn]

I had a similar problem (I have the ATR roller though). Pretty scarey going from all go and not having any stop!!! But I got a resevoir from Summit, and the brakes work GREAT ever since. I know the plastic check valve shouldn't let this happen, but it just did with mine (brand new brake setup too). I would just buy the resevoir (relatively cheap) and give MUCH better reliability to the brakes... It also makes a VERY convenient place to have my vacuum gauge.

Derrick

 

[KWIKR 1]

Vacuum is 12-13 in/HG at idle in drive .tazgn , where did you mount the resevior ? And wich one did you get the alum or steel ? thanks.

 

[Steve Wood]

okay, the booster may be bad. Several have mentioned problems with rebuilt boosters. Let the engine idle, cut it off, wait a minute, and then pull the check valve out....you should hear a big hiss as the air rushes into the booster. I am not sure if this will completely test the dual diaphram units or not.

I run about 13" with my 210 roller and have plenty of vacuum.

 

[KWIKR 1]

Yep I heard the hiss when I pulled the check valve . Brakes worked fine last year before I droped new engine in.

 

[dadmomcat]

resevoir

I had the same problem with the vacuum brakes and weak pedal.I installed a resevoir from summit ( alum ) just did it last night, and the brakes feel about 25% better on a hard stop. Check my cam specs. below. Also it is a nice place to place the gauge. I mounted my set up next to the relays on the driver side. made a 90 degree mounting plate out of stainless. Give it a try, you should get some good resuts.