Brake booster causing soft pedal? w/vid
05-18-2015, 04:27 PM
#31
IHI KING!
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Location: Nashua, New Hampshire, USA
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Correct, when I was pressing on the pedal and my friend opened the bleed, my pedal stayed the same and small amounts of fluid and bubbles came out. We kept doing that until the bubbles stopped. Not sure why the bleed was so slow. We tried swapping bleed screws and make sure it wasn't blocked by debris.
PM sent
PM sent
05-18-2015, 05:35 PM
#32
Rennlist Member
It usually helps if you bench bleed the master cylinder before install. That way you get a lot of the air out before you start the bleed process. Ask me how I know. 
05-19-2015, 03:45 AM
#33
Drifting
I took a longer test drive yesterday evening and the pedal feels just fine and solid. But I'll wait with a report until Monday after my first trackday with the 993 cylinder/booster set up, to say if this works better than the 964 cylinder.
05-21-2015, 04:54 AM
#34
Drifting
How are you doing Alex? Any progress?
05-21-2015, 06:08 PM
#35
Three Wheelin'
Thread Starter
Welll, nothing new really. I had bled around three more cans worth of fluid and after that the fluid seemed to be coming out clean and clear. So I put everything away and started the car, but the pedal is not even a tiny bit different than before. So for now I'm going to return this borrowed MC and put on my old one and decide what to do. Whether I try finding another 964 booster, or maybe order the full 993 conversion. Although the thought of changing the booster sucks, was not a fun job the first time around.
edit: could a bad caliper be giving me this soft pedal?
edit: could a bad caliper be giving me this soft pedal?
Last edited by Mr.Alex; 05-21-2015 at 06:41 PM.
05-26-2015, 01:10 PM
#36
Three Wheelin'
Thread Starter
Finally have some sort of a good pedal. Turns out the place that swapped the booster didn't place this sort of half inch up that holds the pushrod inside the brake booster. The soft pedal and no grab up top was because without the cup I would have to push he pedal a longer distance for the rod to make contact with the MC. The pedal is not perfect, but day and night from what was before. I suppose I might need to overhaul the whole system to get it to be like new.
05-26-2015, 04:52 PM
#38
Drifting
I think Alex means this: The aluminium top, no 16 in the pic goes down very thight on the neck of the booster. The 964 top is like 1-2 mm to narrow so it won't fit over the neck if you don't enlarge the hole with a Dremel or similiar. If you don't do this the top won't sit correctly and the linkage doesn't work as supposed.
I have real pics of this mod in my computer.
I have real pics of this mod in my computer.
05-26-2015, 05:47 PM
#39
Three Wheelin'
Thread Starter
It isn't that Thomas, I'm still on 964 parts. Unless you guys had a broken booster and replaced it with a booster that was missing the pushrod which sits inside the brake booster, than it shouldn't be a concern for you. The booster I bought of pelican did not come with the pushrod because the member sold it with the master cylinder, and when the mechanic pulled the push rod off the old booster the metal cup fell inside and was forgotten about. Normally its a cup, pushrod, and washer held by three plastic tabs within the booster.
07-09-2017, 02:01 PM
#41
Race Car
I think Alex means this: The aluminium top, no 16 in the pic goes down very thight on the neck of the booster. The 964 top is like 1-2 mm to narrow so it won't fit over the neck if you don't enlarge the hole with a Dremel or similiar. If you don't do this the top won't sit correctly and the linkage doesn't work as supposed.
Guys this is all very helpful thanks ...
re pic part numbers #43 - is there a special way to get the two hard plastic pipes (#8 & #7; that run from the reservoir in the frunk) to the vacuum booster off? Of do you just insert a flat edge driver and pop them off?
