RockAuto has an ACDelco Booster part #178515 close out for $202 right now.
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Yes as is where is hope it works if not sorry.. Do these things dry up and rot on a shelf?? Dave

 

The Cardone booster I put on my 89 fit perfect. Only thing I noticed is the gasket was thicker than OEM. Which caused me to have to reseat my cruise and brake switch. I also had to put the rod on the brake pedal before I completely installed the booster. I don't think it would bother me having the brake pedal closer to the floor as my foot always catches on it.

The push rod is something you have to adjust on the vehicle. I had to extend the rod on mine probably a good 1/4" as it was too short. I've read you are supposed to also re-adjust the rod when you replace the master.

You can get a metal booster. I've heard good things about them. I think they cost slightly more than the Cardone booster. Don't know who makes them though.

 

Look I will make the same offer as before I have the booster I took out of My 1990 convert with 57,000 miles on it . When I put the used one in the brakes didn't seem any different till I went out and jumped on them a few times till the ABS kicked in . So as far as I can tell the old booster is fine . Try it on Your car if it works I want $65.00 for it if not throw it away . I'm going to a wedding in Hamden today if You get this and want to hook up let Me know . My home phone # is 860 675 9560 . Will be home from church after 10:00 AM . Wife's cell is 860 989 7590 . Wedding is at 12:00 noon call cell sometime after 1:00 PM if interested . Tom P.

 

Hi Tom P thanks for your very generous offer. I am tied up today finishing a project I have to deliver tomorrow and painfully behind on it. I think I am going to cut the pedal shaft then make a sleeve threaded in the ID at one end and drilled to press the cut off end and weld the pressed side before installing it on the booster. I have a complete fab shop with lathes bridgeport cnc etc for my biz so it is not like I am going to have to pay someone to do it. The real problem is the rebuilders either don't know or do not care. Or possibly the companies that make replacement parts that go inside do not know or care.

 

OK . Sounds like You have all the tools You need to fix the problem . I agree that the remanufactures are trying to cut corners and offer one unit or size to fit all . So buyer beware even if they take it back your stuck with the shipping or work removing and installing for nothing .
Thats why a form like this is so valuable .

 

I have bought 2 boosters from Advance Auto and they fit fine in my 92. I don`t know what brand they were but they were about $150 (rebuilt) and carry a lifetime warranty.

I am suprised you are having so much trouble with the fit.

Matt

 

The trouble is 90 and 91 are a different booster due to rod length than 84 to 89. GM has a different part# for 89 vs. 90 and 91. Rebuilders seem to think if it bolts on it is correct even if it is not correct. I am not willing to give up brake pedal travel just because Cardone and others say it will be fine. if GM thought a booster off an 89 would work fine why would they have a different part # and all the costs involved? All a smart rebuilder would have to do to cover 84 to 91 is to build the the 90-91 spec and provide a shim to go between the booster and firewall for the 84 to 89 cars and remove shim for 90 and 91.

 

I wonder what happens when Cardone gets a 90-91 core to rebuild?

You could give Cardone a call to let them know the 90-91 vette has a different booster than 84-89 and see what they say.

 

The ABS unit preforms a self-test once the Vette starts moving after start-up. Since the unit is located just behind the driver's seat, roll up the windows, open the compartment door covering it up, and had have a passenger listen for the unit cycling when the ABS light appears.

The Hawk HPS pads are high performance street pads - not race or auto-x pads. They do not require any warm up to work properly.

Just as an aside, when testing my 89's brakes after a complete flush, I do a couple of panic stops from 25 MPH on a dry road to check for pedal feel and lack of ABS engagement. The ABS should not kick in unless one or more wheels lock-up and the ABS senses that Vette is still moving.

 

I can not generate enough braking pressure to lock a wheel on a dry road. The tires are good and withing a little over a year old but they are not that grippy to stop a lockup.

Josh I have talked with Cardone on several occasions and while they seem interested and seem to agree might be a difference they don't really offer a solution.

I did talk to bosster dewey as he is the only person I found that would rebuild mine. His prices are very reasonable and turnaround is quick. Another upside is you get a booster with all your hard parts in the rebuild so it will both fit and look original right down to date codes proper plating etc. This is not important to me but if you a show car this must matter a good deal to keep it all as manufactured. He also reccomended no matter what I do to keep my core in case anything i dream up does not work in the long term I will have the proper parts to make it right in the end. He also advised that new old stock boosters will probably have a very short life span unless in an airtight sealed bag and even with that a booster that does not get regular exercise will fail early. Something to consider on a car that has been sitting and possibly something else to do if your car sits in storage... while waming it up to get rid of condensation exercise the brakes a bit to flex the booster.

In the next day or two I will take accurate measurements of the exact differences and if i mod a Cardone generic booster will post pics of what i did to make it work in a 91.

As a last thing if anyone feels these are good tech tips and accurate with some more documentation by me feel free to add them to the ch tips section.. BTW this is not shade tree stuff I am a very accomplished engineer in the race car biz and eqully good machinist..LOL.. Booster dewey seemed very impressed with the R&D done and how it was done and even better a Corvette guy as we discussed how we both squirel away take off parts just in case we need a core later.
Dave

 

Thanks, for all the Booster research as I also, have a 91 Vette.

 

Just to make sure that we're not talking at cross purposes, my point was that a properly functioning brake system won't activate the ABS when braking on dry pavement no matter from what speed you're hauling down. (I've tried triple digit braking in the dry on an airfield and had the same results - no lock-up/no ABS!)

To properly test your ABS system, you need the ABS test module for your year Vette. A shade tree substitute would be braking on a wet surface or one covered with sand, gravel, etc. that will allow a friction-free wheel to lock-up. No lock-up, no ABS intervention. Lock-up, but no ABS intervention - ABS has a problem!

Based upon your latest posts, you seem to feel that you're not generating the amount of braking multiplication that a properly functioning vacuum brake booster should provide. Hope that you've located the problems and that solves your braking problem.

 

Sorry to have to say this, but either your ABS system is malfunctioning or -- more likely -- your brakes are less than marginal. A properly functioning non-ABS braking system should ALWAYS be able to lock up the wheels on dry pavement, and that is precisely why the ABS system was invented. When I stomp on mine on dry pavement the wheels lock momentarily, but after a short chirp from the tires the ABS system comes on buzzing, pulsating and with an "ABS active" light in the display.

If you can neither lock up the wheels or activate the ABS you have what sounds like dangerously weak brakes.

 

According to my Kent-Moore J35890 ABS Tester, my ABS system is fine and working within specs. (I test the system once a year on my '89s when I cycle the pump during a brake fluid system flush at the end of auto-x season.)

Also, ABS was actually invented to maintain directional control of aircraft when braking on wet, icey, or snowy runways when the coefficient of friction for the braking wheels was rapidly approaching zero.

 

According to my real-world test of panic braking on a dry surface -- which results in a quick, non-locked-up, ABS-assisted stop in a straight line with no hands on the steering wheel -- my ABS system is also fine and working within specs. I don't see how we can get different results when both of our systems are functioning normally, but....

BTW, I never said it wasn't useful in conditions of limited traction. But statistically I'm far more likely to need it when the jackass in front of me brakes suddenly for an exit ramp on a fine, sunny day.

The FSM says, "The purpose of ABS is to maintain maneuverability under severe braking conditions on most road surfaces" and to ..."prevent the braked wheels from locking." There seem to be two assumptions here: 1) ABS is expected to activate under certain conditions; and 2) brake lock-up under severe braking is not only possible but expected without ABS assist. If you don't drive on "most road surfaces" then naturally this does not apply to you.

But if you are happy with your brakes, good on 'ya.

 

Hi Tom I am tied up big time this week if you feel like shipping the booster you have I will gladly pay for shipping to see if it fixes it and get to drive this weekend. There is not enough room to mod the 85 to 89 part as I would have to weld on the booser side of the pedal rod, no room for a jam nut. My only other choice is to send mine out to be rebuilt..
Dave

 

Since you said ALWAYS (in caps of course)... Do you think that stock 100% working order base C4 brakes would lock up the 315 series Hoosiers on my track car on smooth pavement? Not a chance.

Suspension, tires, pavement type, and about a million other things play a part in whether the tires lock up.

Your ALWAYS statement is dead wrong.

 

Mr. Beachcomber said:Unless some specific exceptions are noted I think we have to assume that he was talking about an OEM setup. My ALWAYS was in the same vein, kind of like saying a compass always points north. Yes, in geological epochs past the earth's poles have reversed and will again, but is it really necessary to add all those qualifiers?

 

The only qualifier I added was different tires... doesn't seem like too much of a stretch to me.

To take it down a notch, from my own real world testing (which is what you used) base C4 brakes won't lock up 275 series Michelin PS2s on dry smooth pavement. I know the brakes in my 87 are in 100% perfect working order and they don't get into ABS at all with the PS2s on the car. With the stock wheels and junk tires they will lock up all day long if you try.

If you get into the ABS regularly on dry smooth pavement in a stock brake C4 your tires are most likely hard as a rock pieces of crap... or you are an idiot and braking around corners.



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