Lost powerbrakes after WOT?

Is it normal for these cars that you have no power brakes right after WOT? It came like this when I bought it and I've replaced this connection once in the past. I suppose it's a check-valve, but that didn't change anything:

I know there is no vacuum at WOT, so in that regard I figured it was just an old car feature. And a second after the power returns.

But, none of my modern car have this phenomenon, so perhaps it's not normal?

 

I believe most new cars use Hydroboost.. The wifes Hybrid is all electric power acc.

 

That's an odd one, Stefan.

Even my over-cammed engine will make great vacuum at the brake booster once throttle is closed and rpm's are decreasing.

Is power brake function ok during casual street driving?

Devon

 

As soon as the throttle is closed vacuum returns. Which gives an odd brake response, because it is very progressive. At first not a lot is happening and then full brake power is enforced with the same pedal pressure.
During normal street driving everything functions well. It's only after wide open throttle, so basically sprinting away from the traffic light does mean no other car should accidentally try to cross. (That's more often the case, but in my case a little more).
I don't think I have a leak either, because when I unplug the booster later when then engine is off there still is vacuum present.

I don't know, but apparently it's not as it's supposed to be?

Edit: ok. I'll fix the brakes when it's driveable again

 

Haha, I'm currently restoring it. So yes kinda.
I 'd like to know if I have to do something about it or not. If it were normal I wouldn't bother fixing it. Since it's not normal I have another task on my list.
I expect the car back from the painter anytime soon, so then I can reassemble it again, also the brakes. So I'm planning my actions and thinking ahead and this was something that was nagging.

 

I blew one of those check valves out heading into a 110 degree turn in the Riv. Had to stand on the brakes and arm wrestle the steering and then managed to get the car into a hotel parking lot to avoid a 4 way stop that I would have blown thru. Scared the {%[*] out of me. Still can’t believe I didn’t hit anything

 

What type of hose is connected to your valve? If its fuel line hose it will collapse from vacuum. It needs to be vacuum hose. Should be 11/32 if I recall correctly.
https://techtalk.mpbrakes.com/how-to-series/picking-the-proper-vacuum-hose-for-your-brake-system-0

 

No is a vacuum hose. Don't know the size, but it looks correct.
I'll order a new valve and check for vacuum leaks.

 

in the last 4 months my gs has ejected the lid- cap on the booster (check valve thingy ) on start up.. when I back the key off to fast... upon stat up or a quick bump start

 

who make a quality replacement

 

Same thing happened to me, after that I kept the spare in the glove box

 

Well its more like a cough / or small backfire engine rotate backwards slightly.. if i hold key down and crank over engine it never happens.. seems only when i hit the key quick expecting a quick snappy start ...and good by booster vac check valve the middle disappears like a missle The booster is new as is the grommet engine runs great

 

Jup, confirmed. Booster has a tiny hole.
Fits the issue. Has enough vacuum on normal drive, but it leaks away too quickly on WOT.

Anyone experience with " QUALITY-BUILT B1056 Reman; "? https://www.rockauto.com/en/parts/quality-built,B1056,cylinder+head+bolt,5308

 

I have, but the hissing sound is somewhere from the rod. So that won't help.

 

Have it rebuilt if it is an original. It will be better than a store bought mass unit. IMO