RPM fluctuation when braking

BNelsonAz · Post by **BNelsonAz** » Sun Dec 07, 2014 10:28 am

Have a weird problem on the 80 FI. The pedal effort increased, and when you brake the RPMs go downl Is this a vacuum pproblem ya think?

azruss · Post by **azruss** » Sun Dec 07, 2014 11:28 am

this is one i havent heard yet. look at the big hose that goes to the booster. check it for leaks.

BNelsonAz · Post by **BNelsonAz** » Sun Dec 07, 2014 11:56 am

Yeah it's weird. Thereis also a sound from the pedal area like the sound of air escaping .....pshhhhhhht and then it stops when the brake pedal is fully engaged.

narfire · Post by **narfire** » Sun Dec 07, 2014 1:52 pm

me thinks the booster might be pooched. diaphragm might be torn. Have a close look at the booster hose to the intake as well.

4uall · Post by **4uall** » Sun Dec 07, 2014 2:27 pm

Had the same thing happen to me a while back

Ended up being a bad booster. Did a manual work around until I can put in my new booster

BNelsonAz · Post by **BNelsonAz** » Sun Dec 07, 2014 7:51 pm

[quote="4uall"]Had the same thing happen to me a while back

Ended up being a bad booster. Did a manual work around until I can put in my new booster

Right...crud. Was afraid that the booster was bad. Did it doo the "Pssssshhhht" noise on yours too?

divace73 · Post by **divace73** » Sun Dec 07, 2014 11:51 pm

this happened to me as well, a new booster solved the problem.
If you block of the hose that goes to the booster you will find the engine return to normal and braking will be very hard, most probably just like it is now.

4uall · Post by **4uall** » Mon Dec 08, 2014 8:14 am

BNelsonAz wrote:
4uall wrote:Had the same thing happen to me a while back Ended up being a bad booster. Did a manual work around until I can put in my new booster

Right...crud. Was afraid that the booster was bad. Did it doo the "Pssssshhhht" noise on yours too?

She started hissing and that's when I knew I had some booster issues as I had already replaced all my hoses and investigated alternate possibilities. Plus the forum told me LOL

BNelsonAz · Post by **BNelsonAz** » Wed Dec 10, 2014 11:16 am

Thanks Jay and David. One more question:

The vaccum connection on the booster: is it a swivel connection? Is it supposed to move? I'm trying to find other things to replace instead of spending $150 on a booster.

Thanks!

Bill

wizard124 · Post by **wizard124** » Wed Dec 10, 2014 11:55 am

BNelsonAz wrote:Thanks Jay and David. One more question:

The vaccum connection on the booster: is it a swiverl connection? Is it supposed to move? I'm trying to find other things to repace instead of spending $150 on a booster.

Thanks!

Bill

No, It doesn't swivel

seabeelt · Post by **seabeelt** » Wed Dec 10, 2014 2:36 pm

Depends on the booster, some do, some don't. My 71 does not, however a spare on the bench does. It's basically a check valve. AR has them if you take a look at their site.
R/

azruss · Post by **azruss** » Wed Dec 10, 2014 3:13 pm

Bill, the booster hose is not a rigid fit. It sits in a rubber seal with a check valve at the booster. if you are hearing hissing inside the car, its probably the diaphram. There should be a ton of used ones around that are still good. John D and John S and i are setting up a meet with a guy trying to sell 40 boxes of Fiat stuff. This might be a good shopping opportunity for such an item.

RRoller123 · Post by **RRoller123** » Wed Dec 10, 2014 4:45 pm

The connection on my 80FI swivels.

BNelsonAz · Post by **BNelsonAz** » Wed Dec 10, 2014 7:20 pm

azruss wrote:Bill, the booster hose is not a rigid fit. It sits in a rubber seal with a check valve at the booster. if you are hearing hissing inside the car, its probably the diaphram. There should be a ton of used ones around that are still good. John D and John S and i are setting up a meet with a guy trying to sell 40 boxes of Fiat stuff. This might be a good shopping opportunity for such an item.

Hi Russ,

Thanks for the confirmation! As for 40 boxes of Fiat stuff...all I can say is I'm in for a shopping trip!

Thanks,

Bill

RPM fluctuation when braking

RPM fluctuation when braking

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Re: RPM fluctuation when braking

Re: RPM fluctuation when braking

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Re: RPM fluctuation when braking

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