Master Cylinder Questions

[SkylinerRon]

RE; Silicon brake fluid.

Used in my 57 after brake overhaul in 1983, still in there no problems at all.

Ron.

[KULTULZ]

KYBlueOval -

Haven't seen you post recently.

Were you able to get a diagram (PARTS ILL) of the complete system and the circuity of the MC (SERVICE INFO)?

[RICH MUISE]

I almost got to verify an '03 hydroboost setup. A show I did a week ago had an '03 Mustang GT with the hood propped open a foot or so in front.....just enough to see the reserve canister on the hydroboost. The guy was nowhere to be found all day. I was told he was part of the group assisting with the show, so was apparently off doing that. No way I was going to mess with his car too have a look. Anyway, it at least verified that the SOHC GT's had the hydroboost as well as the Cobras.

[KULTULZ]

I almost got to verify an '03 hydroboost setup. A show I did a week ago had an '03 Mustang GT with the hood propped open a foot or so in front.....just enough to see the reserve canister on the hydroboost. The guy was nowhere to be found all day. I was told he was part of the group assisting with the show, so was apparently off doing that. No way I was going to mess with his car too have a look. Anyway, it at least verified that the SOHC GT's had the hydroboost as well as the Cobras.

What I am trying to verify (without the purchase price of a 2003 WSM) is the brake plumbing and MC internal valving.

There are so many caveats (Fr.) using late model braking on an earlier vehicle.

To Wit -

Q - Which front and rear brake setups does it work with?

The Hydro-boost is simply a type of power assist, just as a vacuum booster is a type of power assist. It will work with most of the front and rear caliper setups used on SN95 and Fox Mustangs. A limitation is the lack of master cylinder sizes available for the Hydro-boost. This makes it important to confirm that the volume of fluid required to move the caliper pistons is compatible with the volume of fluid the master cylinder can deliver. If the caliper piston requirement is excessive, the brake pedal will have an overly long stroke, which is very disconcerting for the driver. At the extreme, if it exceeds what the master cylinder can deliver, the piston in the master cylinder will reach the end of its stroke and bottom out, preventing full application of the brakes.

While you're confirming that your Mustang's calipers are a match to the Hydro-boost master cylinder, it's also a good time to confirm your Mustang's front to rear brake bias (or any retro-fit) is in the range of what works well. Fox and SN95 Mustang brakes should have between 70% and 75% front bias (also referred to as 70/30 and 75/25). The more heavily modified the suspension is for improved handling, the closer to 70% the front bias should be. An exception is a street and/or strip Mustang running an extreme 'big-and-little' combination of fat rear tires and skinny front-runners, where substantially more rear bias is required to offset the lack of front tire grip.

Q - How do I confirm my brake calipers are a match to the Hydro-boost master cylinder, and that my bias is good?

You can calculate the fluid requirement of your calipers from the piston area, and then segue into calculating the bias by taking into account the rotor diameters. Or, you can take advantage of MM's Technical Services and let MM's setup engineer do the math. Select the Fox Hydroboost Conversion option, and follow the instructions.

Most of the aftermarket big brake kits listed for SN95 Mustangs also work well on a Fox Mustang. There are some exceptions. Brake systems we've done the calculations for are listed on the Fitment tab. If you don't see your brakes listed, go to the Technical Services page, select the Fox Hydroboost Conversion option, and we'll run the numbers for you.

The brake setups most likely to have poor bias are those put together by DIYers. These systems are often done following dubious Internet directions, or simply because the parts were readily available and easily bolted up. Good DIY mechanical skills don't always coincide with good brake system engineering

.

SOURCE - https://www.maximummotorsports.com/Hydroboost-Conversion-Kit-1999-2004-Hydroboost-in-1979-1993-Mustang-P1618.aspx

You guys are doing this as there is little room left after a COYOTE INSTALL in an older chassis?

Am not complaining, just trying to figure all of this out.

[KULTULZ]

I'll look at my setup, but I think the Ford dealer was guessing wrong. Not sure if the proportioning valve my lines are going thru will allow for a proper determination, but I'll look after my coffee.

Were you able to inspect the setup? The Proportioning Valve would be in the rear brake circuit if it is freestanding (not part of a Combination Valve).

You said new master cylinder, but is it the Mustang style, or Wilwood/standard style? If it is the Mustang style, they cannot be bench-bled. I mentioned that before, and suggested making a bleeder jar with two hoses so you could bleed both at the same time.

Why would you say 'cannot bench bleed' this period OEM MC?

Now you used the late MUST HYDR0-BOOST as you have a COYOTE engine in a '57. Was there no room for a vacuum booster or did you just want to go HYDRO-BOOST?

I ain't questioning or yelling but just trying to nail some information down.

[RICH MUISE]

First of all, I'm not sure anyone on this forum has a Coyote motor. I sure do not. Mine is a '95 Lincoln 4.6 DOHC. I can't remember what John/KYBlueoval's plans are for a motor. I wanted power brakes, and had no other options as the DOHC version of the 4.6 is a very wide motor, with absolutely no room for a vacuum booster. Years ago when I was trying to sort all this stuff out (where John is now), I got input/ recommendations from other members on this forum that had done the hydroboost. It was then I was told the Mustang hydroboost's master could not be bench bled. I believe I was referred to a printed article on that subject, but don't remember for sure. I for sure am not an expert on the different systems and their component compatibility, all I know is I was apparently given good advise as my brakes have always worked well. I'm sure not as well as a complete Wilwood or similar system, but the single piston Granada front discs and '88 T-Bird rears have worked well enough to keep me happy.
This whole discussion started when John was trying to confirm which M/C port went to the front and which went to the back. That's what I was trying to see on that '03 Mustang at the show. I have my front M/C port going to the front brakes. I don't remember how I determined that, but I sure wouldn't have just taken a guess. It was probably info offered by the ones helping me way back when. Last input from John was he thought the front port should go to the back brakes.
Using a Hydroboost is not always because of a space problem, others have used it because of inadequate vacuum produced by their modified/racing motors.

[RICH MUISE]

BTW, the Lincoln Mark VIII did not use a hydroboost. Like many cars factory designed for wide motors, the Lincolns had a recess in the firewall to accommodate the vacuum boosters, which the '57's obviously do not have.

[RICH MUISE]

Something else I've been thinking about......The Mustang M/C has the single reservoir as shown in John's posted pic a few pages back. It is tipped, and it was said the most volume of brake fluid was in the back, so maybe that "larger" volume should be over the front brake piston. I think that's what got John thinking the back port should feed the front brakes. But would that be the best scenario on an unknown damaged/leaking system? We know front brakes do the majority of the braking, so if the reservoir was rapidly depleting to the point where the front M/C piston was not being fed, would you even notice it if it was the back brakes that were not working? For sure you wouldn't notice it as rapidly if the front brakes stopped working. It may be possible that you would end up with NO brakes too late, as opposed to having brakes that obviously were not operating correctly. Does that make sense? It's kinda like those run-flat for 80 miles tires they brought out years and years ago. How do you know you've got a flat to begin with?

[KULTULZ]

John was going to try and go by the dealer and see if they still had a 2003 WSM.

The mystery is how the internal reservoirs in this MC are arranged.

Now to correct something I posted earlier regarding the valving-

The valve pictured previously seems to be a PPV only as I see no provision for a PDV WARNING LAMP SENDER SWITCH and DISC/DISC would not have a METERING VALVE. So what is shown is a true PROPORTIONING VALVE only. But it would not be calibrated correctly other than for the actual car it was released for. An ADJ ANTI-BIAS valve would have to be used as long as the installer realizes the difference(s) between the OEM PPV and the ADJ. One of these things can get you into some serious trouble on the street under the wrong conditions.

I am curious as to why someone said one cannot be bench bled. You couldn't do it on the car as once mounted it is tipped upwards and guess where the air bubble would settle and stay?

Both MC internal bore/piston sizes should be the same as it is DISC/DISC.

Do you have bleeder screws on your MC?

[KULTULZ]

Something else I've been thinking about......The Mustang M/C has the single reservoir as shown in John's posted pic a few pages back. It is tipped, and it was said the most volume of brake fluid was in the back, so maybe that "larger" volume should be over the front brake piston. I think that's what got John thinking the back port should feed the front brakes. But would that be the best scenario on an unknown damaged/leaking system? We know front brakes do the majority of the braking, so if the reservoir was rapidly depleting to the point where the front M/C piston was not being fed, would you even notice it if it was the back brakes that were not working?

For sure you wouldn't notice it as rapidly if the front brakes stopped working. It may be possible that you would end up with NO brakes too late, as opposed to having brakes that obviously were not operating correctly. Does that make sense? It's kinda like those run-flat for 80 miles tires they brought out years and years ago. How do you know you've got a flat to begin with?

It is the MC that is tilted on install. The reservoir will become horizontal (if the vehicle trim is correct - you know how these hot rodders are).

On the old FORD MC system, the rear reservoir was the for the front whether DISC or DRUM. Now some GM are opposite and this is where you have to be careful using vendor kits. That being said, it appears the larger portion of the reservoir is over the MC rear piston. Now one would think because of this the rear of the MC operates the front calipers as they require more juice and as the pads wear will need more fluid than the rear disc (smaller piston size). This is where a LOW LEVEL WARNING LAMP comes into play. It tells you that the fluid level is low (usually on a single reservoir as shown here, the low warning would indicate that the level is low for either port.

Now if ABS and the fluid is low, the ABS LAMP will be activated, indicating a low level and the first thing to do if the ABS lamp illuminates is to check the fluid. If after topping the lamp stays on, then you go to diagnostics.

Now if there is not a FLUID LEVEL WARNING SWITCH in the reservoir (connected by plug) there has to be another method of warning the driver. This is another reason for the need for the manual.

The front disc does the most work, one reason for the rear disc being smaller. The rear pads should last longer than the front and use less make-up fluid for pad wear.

I hope that made sense.

EDIT -

I found online the 2009 MUST OWNERS MANUAL. There seem to be two instrument clusters, one MUST and the other GT.

There is a BRAKE WARNING LAMP, an EMERGENCY BRAKE APPLICATION LAMP, and a ABS LAMP. I would assume that on a model without ABS, the ABS lamp would be non-functional.

If one could have printed out a BRAKE HYD SYSTEM ILL, a HYDRO-BOOST SYSTEM ILL and possibly the MC (2140) and MC REPAIR KIT (2004) application page (along w/ the 2B091 PPV), it may answer a few questions.

Cars have become more complicated as of late.

[KYBlueOval]

Life events have gotten in the way of working on my Ranchero as of late,but they are in the rear view mirror now, so back to working on the Ranchero.
I will visit a local Ford Dealer on Saturday to see if they have a 2003 WSM and will print out the brake system parts etc. I've found that the Saturday  Parts counter guy has very little do do, and my requests are less of a bother. We'll see if I get what I need.
I opened the WEBSITE, for Maximum Motor Sports that KULTULZ posted in post #48 and read all of what they had to say regarding a Hydroboost conversion kit they sell for Fox Body Mustangs.They prefer the '99-04 version of the Hydroboost, which is what I have ('03). A closer examination of the MC that was on the HydroBoost when I bought it( donor car had T.C.) and the replacement MC I recently bought for a NON Traction Control '03 Mustang GT, reveled that the outlet ports of the NEW MC are the same size front or rear, and the MC that was on the Hydroboost when I bought it, has a larger port closest to the radiator. This difference is confirmed, with photos, on the Maximum website under parts ID. 
They also offer a "Brake Proportioning Valve Eliminator Kit for '87-'93 Mustangs", but no mention  of a kit for '94-'04 Mustangs. I'll call them today and see what they have to say.
To be continued...... 

[KULTULZ]

They also offer a "Brake Proportioning Valve Eliminator Kit for '87-'93 Mustangs", but no mention  of a kit for '94-'04 Mustangs.

Those kit(s) are meant only for the original install on a MUSTANG. One will enable you to disable the PPV so as to keep the body (DIST BLOCK) and not disturb the factory plumbing and the other giving enough plumbing parts to eliminate the original valve completely without a total plumbing redo.

There is little choice other than an ADJ PPV. This is how you have yours, correct?

[KYBlueOval]

You are correct, I have not installed the PPV, and yes I have a Wilwood Proportioning Valve in the rear circuit.
The front brakes are connected to the port closest to the firewall.

[KULTULZ]

First of all, I'm not sure anyone on this forum has a Coyote motor. I sure do not. Mine is a '95 Lincoln 4.6 DOHC.

My mistake. I should have posted modular.

[KULTULZ]

Life events have gotten in the way of working on my Ranchero as of late,but they are in the rear view mirror now, so back to working on the Ranchero.

No problem. I just didn't hear anything and was wondering.