mustang hydro-boost

[ROKuberski]

Gasman,

A question for you.  I have the power boost unit now.  After examination, I am not going to use the adapter plate.  It appears that the integral push rod that goes from the brake pedal to the boost unit is the right length right out of the box.  I will drill the firewall for the boost unit bolt pattern.

My issue is the push rod inside of the boost unit that activates the master cylinder.  The instructions in the box show a push rod with a spring on it.  Since I intend to use my 1967 m/c, I don't have this rod and even if I did, it would likely be the wrong length.  Is this a solid rod between the piston in the boost unit all the way to where it pushes the piston on the m/c?  Hard to tell in the sketch (see below.)  I can make a new push rod, but I am not sure what the function of the spring is.

Thanks,

Rich

[ROKuberski]

Gasman,

Disregard.  I think I figured it out.  I found this on the internet.

Rich

"The spring and rod are an important part in the system; the spring puts tension on the booster piston so it releases the pressure on the rod and doesn?t stay engaged to the master and drag the brakes when you let off the brakes. The disc on the inner end keeps the rod centered in the booster rear cup and the retainer of course keeps the spring in but also centers the rod to line up with the master cylinder indent. If the rod were to drop out on either end it could cause your brakes to apply and not release in a panic stop of just plain fail. So if you?re fabricating these pieces remember these dimensions are for a 2001 Silverado 1500 with 4 wheel disc brakes, the Hydroboost and master cylinder are for the same truck. I have no idea if the rod and spring is the same for any other year or model truck. What I have found is that the rod is a .065? longer than the distance between the two rod cups. So it puts a little preload on the master thereby insuring that the rod doesn?t drop out.

Rod diameter 0.34? with a length of 3.16? it appears to be as hard as a grade 8 bolt. The rear spring seat disc is .970? diameter with a thickness of .040? and placed .25? from the inner end and it is made of plastic. The spring is 4? long and .945 diameter. The wire thickness is .073. It feels like a 20 ? 25 Lbs. spring tension."

[RICH MUISE]

Just for the info, what vehicle did you purchase the boost unit for? My unit from the Mustang was not the correct length for the connecting rod to the pedal, but I never considered the fact maybe the pedal assembly location with a little work might have been moved forward or backward to compensate. Keep us posted on that connection please.
I guess I never read what your reason is for the  changing of the master from a boost style to the traditional. Is it because of the appearance, the fact that you already have a new traditional one? Along those lines I have to wonder why Ford didn't use the traditional style, at least in the later years.

[ROKuberski]

Rich,

This boost unit is from a 1977 LTD.  As far as I can tell, 1975-1979 full size Ford/Lincoln/Mercury are all the same. 

I just measured from the outside face of the firewall to the center of the bolt on the M/C link and it is right at 6", same as on the hydro boost unit.

I think you know that I bought a 7" vacuum boost unit with special bracket for my car 3 years ago.  Twice I tried to get this pile of parts to work correctly.  I could not.  To the credit of the seller, they were willing to work with me to get this working, but now that I have power steering, I can use the hydro boost unit.  As of right now, all that I have to do to get this working is figure out what to do about the pushrod that goes from the boost unit to the master cylinder.  Of course I still need to see what I need to do for hoses too.  The supply hose from the PS pump is long enough to go to the boost unit.  I have not verified if the hose end connection is correct.  I will need to get a hose from the boost unit to the PS gear box and a return line.  I am mounting the boost unit upside down so that the hydraulic connections will be on the under side.

I am also wanting to use my 1967 Galaxie master cylinder.  I don't think that will be a problem.  Hoses won't be a problem and the pushrod is the only thing that I have to either source or make.  I'm still working on that issue.

Here is where I got some of the information on the boost unit push rod.  http://thehollisterroadcompany.com/hydroboost.html

He gives pretty detailed information.  However, given a choice, I would prefer to source a part rather than make one from scratch. 

Rich

[dgasman]

Is this the pin you are looking for ?  if it is send me your address and I will mail it to you

[ROKuberski]

Gasman,

Holy Smokes!! This is exactly the part I am looking for.  I would be glad to pay postage and for the part.  I've been all over the internet and around town this afternoon.  I even went to a local Ford dealer.  He took my information and said he would have to dig out the microfiche reader to check, but he was not hopeful.

Richard Kuberski
6359 Holman Ct.
Arvada, Co. 80004

Thanks,

Rich

[dgasman]

Its in the mail and Mr. postman says you should have it by Thursday. Don't worry about the postage , glad I was able to help..

Kent

[ROKuberski]

Kent,

Thanks.  After searching for this part, I was convinced it was made of unobtanium. 

I appreciate you help with this.

Rich

[RICH MUISE]

Wow, that's pretty awesome!! Way to go Kent...gotta be worth at least a few applauds!

Rich..I'll be anxious to hear how this works out....if it does, I may eventually change because I like the old style masters much better.
I'm not sure if I recorded the connecting rod on the Mustang unit, but I'm sure it wasn't 6".
1977 LTD... you're not going to have to mess with metric adapters either.

[ROKuberski]

Rich,

These hydraulic fittings come in so many sizes that I don't know what they are.  I will pull my supply line to the new gear box and try that on the boost unit.  If it fits great, if not, I'll just haul it all to the hose shop and have them make what I need.

As to selecting 1977 for the boost unit, that is in the middle of the range of what I found in my research.  That is, 1975 - 1979 full size Ford/Lincoln/Merc all about the same.

The length of the rod from the brake pedal to the m/c may be longer than 6", after all, it has to go into the m/c.  My measurement was from the back of the m/c (which is visible from under the dash) to the center of the bolt.  That equates to the measurement on the new boost unit in the picture below.  As near as I can tell, the push rod on the boost unit is not removable or adjustable.  In that regard, I just got lucky.

Without the help from the part from Kent I was going to have to try to fabricate the rod from the boost unit to the m/c.  I was not able to find one in a local salvage yard (I think all of the cars of that vintage have gone to the crusher already) or from any parts supplier.  I will make measurements and take good pictures just in case someone wants the information.

As many of us know, without this site, we would be fumbling around in the dark.  Kent is the second member to offer me a part for free.  Years ago, someone gave me the windshield washer tips, another item that I could not find. 

In the pictures below, I installed the body of an old m/c so you can get an idea of how it will look.

Rich

[RICH MUISE]

I like the look. When everything is said and done, post a list of part numbers if you would. Just guessing, I'll bet the connecting rod is 1-2" longer than the later Mustang version's.

[BWhitmore]

Question:  from the looks of the hydroboost unit itself it appears quite heavy.  Without reinforcement or bracing to the firewall is there any concern about flex to the firewall? 

[ROKuberski]

Yes, it is heavy.  Mounting it will capture not only the firewall, but the bracket that holds the brake pedal.   If there is still some flex, I have considered adding a brace from one of the bolts on the m/c to an as yet unidentified part of the frame or lower part of the firewall.

Rich

[RICH MUISE]

Weight will not be a factor, they're not that heavy. The firewall itself is pretty strong, but just as a master cylinder would, it bolts thru the brake pedal bracket as Rich said. Maybe if someone were really sanitizing their firewall and removing the spot welded, butted flange it might be an issue.

[ROKuberski]

I've got the master cylinder out and doing a test fit.  First impressions are trouble.  It's very close to the exhaust manifold and the return and supply line may interfere.  It's also very close to the gear shift.  The push rod is also long by about 3/8" of an inch, but I can easily deal with that, if that were the only problem.  Break time and thinking time.

By the way, it cannot go in the position where the hoses are on top.  Then the protruding cylinder really interferes with the manifold.

Rich