HYDROVAC puking brake fluid into intake?!?!

pfarber · Post by **pfarber** » Tue Jul 25, 2006 3:22 pm

Man, my CCKW just loves to cause trouble.

I was bleeding the brakes (engine idleing, girlfriend pumping brakes, I was bleeding them). The engine would run rough when she would pump the brakes so I was at the carb upping the idle as she pressed the brake pedal.

Then IT happened.

SMOKE!!!!

Engine stalls then I hear fluid running into the intake. I take off the carb and a pool of brake fluid in the intake.

ANY ADVICE? Is there a check valve that may have failed? I have not opened the manual yet as I am hoping that others have experience this and know of a solution.

42cckw · Post by **42cckw** » Wed Jul 26, 2006 7:43 am

If brake fluid is being sucked into your manifold, the hydrovac has failed and is probably totally full of brake fluid. It has nothing to do with the check valve at the manifold being bad ,as the job of the check valve at that location is to retain vacuum between it and the hydrovac. There is a long learning curve to owning a CCKW

I am still in the infancy as are most cckw owners, depending on what series your hydrovac is will make the difference between rebuild or replacement, vov sells hydrovacs

Karoshi · Post by **Karoshi** » Wed Jul 26, 2006 11:27 am

Then IT happened.

SMOKE!!!!

Could be engine oil, what type are you using? Not all of it is suitable.

pfarber · Post by **pfarber** » Wed Jul 26, 2006 7:24 pm

At this point I higlhy doubt that the fluid in the INTAKE is oil. It didn't smell or look like oil.. the 'upchucking' sound I heard standing at the carb sounded like it was coming up the vacuum tube.

My pinky finger in the port also came out wet.

If there is some other diagnostic I can do to rule out ol, please let me know.

pfarber · Post by **pfarber** » Wed Jul 26, 2006 7:43 pm

Oh wait.. you were be SARCASTIC.

TO BAD YOU DON' KNOW THE WHOLE STORY. THis is a SECOND problem. How do I know this?

SIMPLE:

WHen I was getting the smoke in the exhaust I had the PCV tube (that metal tube that goes from the top of the valve cover to the vacuum line off the carb) OFF. That meant that there was no way suck the fluid out of the hydrovac.

Anythe else you would like to know or do you know it all? hahahahahahaha

dr deuce · Post by **dr deuce** » Mon Jul 31, 2006 5:35 pm

You MUST take the check valve apart and clean it or it will let gas fumes into the new hydrovac and ruin it.

Fernando Mendes · Post by **Fernando Mendes** » Sun Mar 16, 2008 10:20 pm

"....ENGINE MUST NOT BE RUNNING DURING MANUAL BLEEDING....."(page 12-7,TM10-1563)

thierryb · Post by **thierryb** » Mon Mar 17, 2008 8:27 am

At that point you have no other choice than repair your hydrovac or replace it. If fluid came up to the engine, many of it must have migrated from the hydraulic cylinder to the air cylinders. You must have a damaged cup somewhere.
From my experience DO NEVER install a NOS hydrovac without having checked it, cleaned it and greased it. After some year of storage the pistons/parts are stuck and a mixture of storage oil + water + light rust may ruin this new unit if you use it without cleaning it.
If it can help here are some picture of a type I hydrovac I rebuild last year :

http://thierry.becker.free.fr/HydrovacTypeII.htm

Thierry.

The GMC CCKW

HYDROVAC puking brake fluid into intake?!?!

HYDROVAC puking brake fluid into intake?!?!

Smoke!!!!

Manual Bleeding.