So I've confirmed that my brake booster is... well junk. Under the dash yesterday and there was brake fluid running out around the boot. Which explains the loss of fluid I had after I did the brakes. The booster has been hissing a while and I guess that the leak just made that worse. So it'll need both the master and booster replaced. (Fun)

My questions are as follows... is there anywhere to get a halfway decent unit for an 84 still or am I SOL? All I came up with was Cardone doing a reman service on my own and based on prior experiences with them I plan on staying away. Can I source the diaphram? I reached out to a few places and no one responded or could answer what was inside. New old stock maybe?

I have seen hydro-boost conversions as well. If that's the case I'll look more into that route. Just feeling for options at this point.

The master cylinder seems like the easy part. I'm not so much concerned with that aspect.

Any input is appreciated. Thanks in advance.

 

Mine had been replaced with a newer metal 85+ metal unit when I bought it. I had the same issue. So I just bought a new dual reservoir master and another cheap metal booster after I had no luck sourcing an actual 84 booster.

From what I read if the master leaks, it will eat up the diaphragm in fairly short order. I did have to adjust the rod a little with mine to get it working right.

 

yeah. It seems any 85+ one that comes up is a crap shoot if it's plastic or metal. But that honestly is probably the easiest route.

 

I am talking about one of these cheapies. At the time I think I paid $85 or so on ebay. It obviosly can't be as good as the oem sized one but it works well in my setup and I don't know what a stock one feels like anyway.

 

Just eyeballing it, that looks about the same size overall as my girlock unit currently in the car. Gotta be better than what I've got now and if it fits it ships so... I'm pretty sold.

 

@Krusty84 When you said you had to adjust, what did you mean. Presently I have a ton of brake boost and a stupid aggressive pedal that is trying to launch me through the windshield with even the slightest tap... I am assuming the part that engages the plunger on the master needs to be adjusted in a little to take up some travel? I am also wondering if there is a proportioning valve difference.

 

Figured I'd update this. Once I got the adjuster figured out on the master it drives great. The booster is still a little over boosted, as in free travel is very light but the brakes still have good feedback. I'm pretty sure the booster/master was foobar for a long time because this brakes surprisingly well and better than since I've had it over the last 15 or so years. It hasn't left me wanting to do a brake upgrade like I thought I did last year when it was difficult to stop with the extra power... ie driving faster lol. I'll link the unit I bought here. No complaints with it. It fit fine except I had to ding one small spot to clear the throttle cable and that was only because it was close... it really didn't need it. I will reccoment getting or building a plunger adjustment tool however.

 

My old master cylinder started leaking out the rear after bench bleeding it and using speed bleeders. After I get a new one, next time I change brake fluid down the road. I'll just go back to using vacuum to flush brake fluid. Will probably get regular high quality bleeeders and put speed bleeder thread sealant on them so I don't suck air when using a vacuum on the bleeder.

 

Hello 84 4+3,
When I saw you mentioned about your "stupid aggressive pedal" in your Corvette I just remembered something that might help you. When I first bought my C3 the brakes in it were incredibly powerful and would put you into the windshield easily. I took it to a dealer and they could not sort it out, I do remember watching the tech drive my Corvette very fast in the parking lot and slide to a stop. I warned him...

I thought it was over boosted but it turned out to be the master cylinder itself that was doing it. Don't ask me how as I don't know. It was super sensitive and I got used to it thinking it was a Corvette "thing".

One day at 70 mph on the beltway around Washington DC I entered a clover leaf exit rated at 25 mph and when I pushed the brake pedal it had locked up. It was like there was a brick under the pedal and I got nothing from the brakes, thank goodness my E-brake was working. Between the four speed manual and the e-brake I was able to get home safely.

Just be aware that another Corvette with the same type brake symptoms had the "master cylinder" be the cause for the super sensitive brakes.

I replaced the MC and the brakes were like a normal car with power brakes, no more dashboard encounters. I would also consider the M/C as a potential cause for "Super Brakes" and not just the Brake Booster. Stay safe and enjoy your Corvette

 

I don't think it's an issue so much as I'm not used to everything working right. It won't launch me to the windshield now unless I really need to stop. I had dad drive it because he's more used to old vehicles and he said it feels like his 77 did and most older cars so I'm not worried about it. I'm used to trucks with spongey pedals so that's a bit of a shock to me is all. I for sure had the pushrod adjusted wrong though as free play was zero in the other thread.

In short it should have more boost than stock (slightly larger booster) but I don't think it's over boosted. I think the parts are working how they are supposed to and I just am not used to it..