Hydroboost mounting plate

Does anyone make these or have a drawing I could use to make one?

Check with Admin. He uses them on his swaps frequently.

I removed my Willwood tandem MC because I felt the system was OK but I wanted something better.
The Willwood worked but I never got a truly hard pedal. The bottom fittings on the Wilwood MC were difficult to seal, another thread on this forum addresses this.

I bought a 2002 Mustang HB unit on Ebay, it came with a proportioning valve. I found a HB mounting plate on Ebay. I have also purchased Metric to AN6 Steel high pressure fittings for the HB, I was told by HydraTech that the Ford HB's prior to 2000 had SAE threads.

Today I ground the eye of the pushrod and rounded the end of the shaft where it was flat and ran a
10 mm x 1.5 Metric Die down the shaft. At this point I have to enlarge the hole in my sloan firewall plate and do a trial fit before drilling any holes. I also have to see if I need to angle the mounting plate.
Note: The shaft is crimped into the HB end fitting, all the Die work has to be performed in situ.

HB Plate



Stock shaft



Threaded 10 x 1.5 mm



With mounting plate.



Plenty of room here for the HB

Hey Mike, What is the angle of the hydroboost unit when mounted to the firewall?

Rob, Have not checked that yet, have to enlarge the firewall plate hole for a trial fit. Eric's plate shown in an earlier thread has an angle and the Ford plate I removed also had an angle but I don't know what angle the Ford firewall is set at. I will expand this thread, as and when I get more data.
Is the HB angle critical?

Since you are not re-drilling the pedal clevis mount point, the HB body should set at the same angle as the factory MC. I recently posted what it was somewhere, just measure it off your cereal bowl.

12.4 degrees

Please remember guys that my sloan plate is not flush with the factory booster mounting holes.

CORRECTION: After slaving all day to enlarge the hole in the firewall plate and drilling the four HB mounting holes I realised that the plate is flush with the firewall, I mistook the stiffening flange around the big pushrod hole in the firewall......sorry.
WARNING: If you have a sloan stiffner plate (Stainless steel) and you plan Hydroboost, do the hole cutting and drilling before you mount it on the car. It's a b---h to do it in-situ.

As long as the plate sits flat on all three firewall holes, then you adjust the HB unit angle to 12 degrees. plus or minus a half degree will be fine. It's the inner rod seal/s that wear out prematurely if the pushrod angle is wrong.

I assume that the 12 1/2 degrees is nose UP on the Master Cylinder end. This would place the MC resevoir almost level.

The MC reservoir seems to be sit about 15 degrees nose down to the MC center line.

See the CORRECTION in my previous post.

I thought all the sloan plates were aluminum....you have a steel one?

Heres the setup without the car as stock ~ 12.4 degrees


Heres the setup drilled 3/4" up on the pedal ~ 10 degrees.

So you are using the porsche brake clevis? I think I tossed mine with the brake booster.

supes6 wrote:So you are using the porsche brake clevis? I think I tossed mine with the brake booster.

Ooh. You want to keep that though.

My sloan plate is the large style and stainless steel, really tough to cut and drill.

I love your mock up picture, wish I had a scrap shell that I could cut the brake/clutch/firewall section out of it, photograph it from all angles so the future hybrid builders could see all revealed.

fliermike45 wrote:...photograph it from all angles so the future hybrid builders could see all revealed.

You bet!

Grenade Hybrids should have consulted with you guys..... maybe they would have gotten the cereal bowl mod right.. Every pic I've seen the bowl had to be chopped/rewelded to clear the driver's head.

Mike, on your setup, could you slot holes on the square HB adapter plate that matched the firewall vertical holes and give you some angle adjustment?

Looks like I'm going to have to do that, I have jigged up 12 degrees on the bench and it makes a big difference. We need to talk about a billet angled plate, will send you a PM tomorrow with some sketches and ideas.

Here are the pics of the Ford Hydroboost set at 12 1/2 degrees.

Your answer is your cereal bowl, just drill the HB plate 72mm x 72mm to match the cereal bowl....longer pushrod of course.

Cereal bowl went with the rest of the redundant stuff, do you have a spare one?

I use mine for mock-ups. IIRC there is like 34mm extra length of a pushrod when it is used.

Autoatlanta has them for twenty bucks or so.

Cereal bowl hits the motor! you'll need to modify the bowl to make it fit, then your booster will be to far forward. You need to mount the hydro booster as close to the fire wall as you can. Also move it 1/4" towards the driver side strut tower, that will give you better clearance as well. The angle looks to be to great, The push rod has to determine the angle of the plate. It has to go in and out perfectly straight or it'll bind on the edge of the hole where the push rod goes in.

In that case, mod the clevis for the offset.