Brake vacuum Check Valve

Hello everyone -

need to replace the brake servo check valve (near the manifold) -Its sticky when cold.

The Dino has the original part, the check valve is 14 mm (in and out diameter) ( I measured the diameter) - The car is an early 71- 01296 (M Series). The replacemnt valve that I have is a 12mm diameter valve (in and out). The hoses (from the manifold and to the front - servo) are made for the 14mm dia interface. Very loose (too loose ) fit even when titening the clamps.

Any replacement (corssreference Alfa - Fiat ) for the 14 mm part - Its a BONALDI part?

Thanks in advance and Merry Christmas everyone

Pietro

 

Pietro,
Before you toss it in the 'save' pile of old Dino parts and chase after a replacement, put on some nitrile gloves then spray some carb or injector cleaner into the check valve cannister, place your thumb & finger over the ends and shake it well. Then let it soak for a bit. Next, close both ends again and shake it; listen to the little piston/ball/plunger rattling back & forth inside (like when you shake a can of spray paint). With luck, that should help the fluid break up any solid gum, sludge...whatever you want to call it. Empty the now-black fluid into a suitable container and repeat until the fluid comes out clear and the piston no longer sticks in the valve cannister. If you have compressed air, a blast into each end of the empty-but-still-wet cannister might also help to dislodge any debris. Flush it again until the fluid is clear, blow it out then install it (with the arrow pointing towards the intake) and give 'er a cold-start check.

If it's still a bit sticky, a night spent in a can of carb cleaner, followed by a cold water rinse (don't forget the gloves) and a blast of air to completely dry the insides, should finish it up.
I don't know if the piston/ball/plunger is stainless, so a very light dusting inside with WD40 when you are done might prevent it from rusting. Perhaps someone knows if that's necessary.

'trust this old back-yard mechanic trick will work; let us know.
Buon Natale a voi e ad il vostro,
Coop

 

Grazie mille Coop -

I will try it.

Pietro

 

My valve is missing, can someone post a pic ?
I can certainly tell if it is Alfa.

Thank you.
Happy Holidays!

Alberto

 

Alberto -

this is the 12 mm version (the 14 mm one is identical but is on the car). 12 mm is the diameter on either end (smallest diameter).

Cheers

Pietro
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Definitely not Alfa as it would be threaded on to the manifold,
and Dino's substantially smaller. Now I got to find one, or two.

Thank you!

Alberto

 

When I checked mine for function it worked sometimes, sometimes not. I just added another valve from the local parts store on the side away from the manifold. I don't recall any problem with the tube size, so maybe mine had a 12mm valve.