If you have hydroboost, you need to do this

[Morella]

Hopefully this picture attachment will work.

I ran across a serious design flaw with my 76, with Hydroboost. There is a drip pan under the booster unit with a drain hole strategically placed so that if the boost unit leaks, the fluid will go down through the hole and into the steering column boot and shift shaft bushing, destroying them both.

The modification is to turn the drip pan upside down (of course you have to pull the booster to get the pan out) and weld a little piece of tubing onto it, mating up with the hole, so that you can put a scupper drain hose on it. I used 3/8" OD steel tube and fuel hose. Any fluid spillage can then drain out the hose and onto the ground.

Of course if your booster has been leaking for a while, the rubber parts may already be destroyed. I happened to luck out in that I was replacing my steering column anyway. I made a bushing for the shifter shaft out of rubber hose and a clamp, which should hold it until I can find the proper one.

So the moral of the story is, look in that pan under the boost unit every now and then and make sure that it is absolutely clean, no splilled fluid in it. A new booster is only about $150, so if it's leaking at all, just replace it. Then while it's out, you can do this simple modification.

-denise

[The Rage]

I have hyrdoboost in my 1980 Chevy C10..Great pointer!..I'll be sure to check this out!..

BTW, have you thought about ever switching to vacumn boost instead?..OR is the hydro actually "better"? Thanks

[Morella]

As I understand it, the emissions changes in the mid-70's resulted in an insufficient vacuum to comfortably work the power brakes. It might work with a large booster, but then the clearance would be kind of tight. The gross weight of this vehicle is 8200#, more than most light trucks, and it has special brakes. The drums are enormous.

I found another problem with the hydraboost, and this one was really serious. The booster instructions said that I had to reuse the pushrod, spring and retainer between the booster and master cylinder. I removed these, and found that the pushrod was held in the center of the piston on the booster side by a frangible plastic disk, which of course exploded into a million pieces. The part is very difficult, if not impossible, to find. My husband came up with a really crazy solution, which was to make one out of the top of a presciption bottle, and I think it's actually going to work. I'll try to post the somewhat fuzzy picture...the end with the Walgreen's cap goes into the booster, and the spring goes around the rod on top of it.

-denise

[76Eldo_convertFI]

I had the same problem when I replaced my booster with a Cardone. I contacted Cardone tech support and they sent me one free of charge. :shock: Please post pictures of your custom "pill bottle top" when done. I too was planning on making one up myself before I called Cardone.

[Morella]

I did post a picture. You have to click on the link to view it, and then you have to squint really hard because the picture is kind of blurry. My camera either shoots macros or landscapes, not much in between.

Someone else told me to contact Cardone, so I filled out their contact form. I hate talking on the phone. Whether or not the new washer will be an improvement in material, I don't know.

It looks like all I have to do is separate the brake cylinder to install the right part when I get it, which should just take a few minutes. Hopefully there is room to pull it back a little.

I asked for the spring retainer too, because the middle part is made out of plastic. I don't why they design brakes with plastic parts in them, except that back in the 60's and 70's, there was this enormous push to make everything out of plastic. They used to show us films in grade school about how wonderful plastic was, and even at age 6 or 7, I new better. I've seen master cylinder kits with plastic pistons in them, really bad news if you ask me.

-denise

[Morella]

Do you happen to know who you talked to at Cardone? I just got a reply from them, and they say that don't have those parts.

So I guess maybe the prescription bottle cap is there to stay. Maybe I should sell them. :roll:

-denise

[76Eldo_convertFI]

Do you happen to know who you talked to at Cardone? I just got a reply from them, and they say that don't have those parts.

So I guess maybe the prescription bottle cap is there to stay. Maybe I should sell them. :roll:

-denise

Sorry, don't remember who I talked to but I called them. I really doubt that you'll get any help via email.

What did you use on your pill bottle top to keep it from pushing off the back side of the rod?

I was thinking of making something from sheet metal that's the same thickness as the original retainer, cutting it in the right size diameter, drilling out the necessary hole, then brazing a collar (like a brass bushing) on it, cutting slits into the sides of the collar, splitting it in half and using a "C-clip" to hold it onto the rod's groove via the collar's slits.

[Morella]

I made the hole in the center of the disk a little smaller than the groove in the rod, so it snapped into the groove tightly. It's a little larger in diameter than the spring, so the spring should hold it tightly against the piston on the booster side. I don't know how long it will last. Maybe a metal backup washer between the plastic washer and spring would help.

I like your idea with the bronze bushing. I had to stare it at for a long time, but it finally makes sense.

-denise

[76Eldo_convertFI]

I like your idea with the bronze bushing. I had to stare it at for a long time, but it finally makes sense.

-denise

When I mentioned "splitting it", I meant after brazing the bushing on to the sheet metal circle, splitting the whole thing in to 2 halves. The bushing should be the same diameter as the rod groove so when the c-clip is installed it fits in to the groove & holds the halves together. Might also help to have the bushing double sided and use a c-clip on both sides. The front side bushing would need to be the diameter of the rod.

My problem is that I'd have to take my booster apart to measure stuff. Can you tell me the diameter of your "cap" and the hole diameter? I'll store this info and when I come out from under my other projects, I'll try to make one.

[Morella]

Well, I made a nice long post about this, but then I was asked for my username and password again and it was thrown out. I hate computers.

The most important thing was, it's too late to measure it because I already put the thing together, but at least it works.

-denise

[76Eldo_convertFI]

It's completely unbelievable that we can purchase rebuilt boost units but no one makes replacements for the stupid spring retainer for the rod! :evil:

The hydraboost was used on more GM vehicles than Cadillac and I can't fathom that there aren't replacements available. :? All I know is that every time I hit a junkyard, I'm going to be taking master cylinders off looking for these babies.

I'll dig into my Hollander exchange books to see what other vehicles used the boost.

[Morella]

I'm not sure if I want the original one! Considering that it was shattered when I pulled it apart, a metal fabrication might be a better plan.

So far, the bottle cap fix is still working, but I'll pull it apart in a couple of months and see how it's going.

-denise

[76Eldo_convertFI]

I'm not sure if I want the original one! Considering that it was shattered when I pulled it apart, a metal fabrication might be a better plan.
-denise

According to Hollander, the hydroboost was installed into the mid 70's Chevy & GMC 30 series trucks & vans. If you spot one at a bone yard with a "30" on the fender, it may have a hydroboost.

I think that as soon as I get the wife's Regal back on the road, I'm going to pull my master cylinder off and measure everything on the rod and the disc just to have the dimensions BEFORE it shatters, HEHE!

[Terrible One]

Denise,

I just wanted to thank you for your helpful post! Today I took apart my Hydroboost to clean it and check it out, etc. My little plastic piece was shattered as well! I used your idea with the pill bottle cap, which seems to have worked perfectly. I think I'm good to go on brakes now, with my overhauled Hydroboost, new master cylinder, new brake lines, new rear calipers, and new pads all around 8)

So is your Hydroboost working as of right now?

Thanks again, I would have never thought of something like that.

[Morella]

Yes, mine is still going strong, after a couple of months. I haven't had time to take it apart and look at it again, with a new addition to the family (a 76 Chrysler), but the brake pedal feels perfectly normal. I wouldn't be terrribly surprised if I just forgot about it and left it that way forever.

My husband comes up with these ingeniously simple ideas. For instance, I needed to enlarge some 1" caster mounting holes in my hearse to 2". I went to Ace Hardware and asked if they had a step drill for wood, and an old man there told me, no, there's no way to enlarge holes once they've been drilled. So I made a guide out of a socket and some masking tape and junk and that worked fine. Then my husband came along and said, "Why don't you clamp another piece of wood behind it, and then run your arbor bit through the center of the hole and into it?" Duh! Why didn't I think of that?

-denise

[Terrible One]

Well I'm glad to hear that it's still going strong, gives me some hope. I havn't had time to test mine out yet, and probably won't 'till January or whenever the car is finished, but I'm sure it will work fine after seeing the stock plastic piece!

[frankenstang57]

:evil: Look at picture, "MMMMMM, BEER...." :lol: :evil: