1965 Dual Master Cylinder help

[ShowMeGuy]

Ok..... I've done some searching here and found the link where I seen a MC from any Mustang with front discs and drum rears would work good in the 65 Tbirds with some modification to the strut town brace.

I found RustyNCa link where he shows Raybestos MC36251. I couldn't find anyplace that had that but we were able to find a MC from a a 68 Mustang with a 302. I measured it it's pretty much right at 7" total length.

The problem is I cant get the bracket that sits atop the strut tower on without hitting the MC. I doesn't look like that is an issue with his pictures. Has anyone else ran into this issue? I dont' wanna to just start grinding away because i'm concerned that the braces which I know need modified wouldn't work.

My next thought is did the PO change out the booster? it's about 6 1/2" deep from mount to mount... Any thoughts?

I Know pictures would help but I'm still without a camera.

TIA. ShowMeGuy

[simplyconnected]

You may want to revisit his pictures:

Got in the mood to drive ol Lola, and here are some photos I took this morning for you.

In the photos you can see where we notched the brace (I thought it came out looking pretty factory ). In the third photo you can see how we ran the brake lines. The lines going into the tee are the factory lines. The front line is a new line that joined up to the original hard line. So we didn't change the factory lines at all.

[Guest]

Hey Guys,
Thats pretty and a darn good ideal! Sometimes a little thinking goes a long way. Gotta love this web site!!!
Richard D. Hord

[ShowMeGuy]

You may want to revisit his pictures:

simplyconnected, Yes those are the pics that i have downloaded to my PC... I can see where he had to modify the bar going from the strut tower to the center of the rear hood. But in my case I can't get the piece that the bar connects (3 bolts above the shock and is kinda dished shaped) to without some modification as it hits the rear of the MC.. I was hoping to see if that was also modified before I go grinding away and finding out it's not the problem.

Thanks!

[ShowMeGuy]

So I went ahead and buzzed off that little 1/4 or so of that bracket. I have one more brake to bleed. Hopefully the brakes are better. As I found the POs cobble of mess and split the Tee a the MC. Keeping fingers crossed...
ShowMeGuy

[simplyconnected]

ShowMeGuy,
How did you plumb your combination proportioning valve to your M/C?
What size piston was in your old and new M/C's?
Do you use a pressure switch for your brake lights? Where did you put it?
Did you use a residual valve?

I sure wish you had pictures. - Dave

[RustyNCa]

ShowMeGuy,
How did you plumb your combination proportioning valve to your M/C?
What size piston was in your old and new M/C's?
Do you use a pressure switch for your brake lights? Where did you put it?
Did you use a residual valve?

I sure wish you had pictures. - Dave

Well, in my case.....

We didn't run a combination proportioning valve to the M/C.

We didn't check piston size in old M/C vs new, we didn't see that as a concern.

The way we did it, all we changed in the system was the M/C and a small bit of tubing, was very little change to the system other than the dual reservoir so you shouldn't need to worry about the brake switch etc.

No residual valve, my understanding you only need to run those when your M/C is lower than your Wheel Cylinder's which isn't the case here.

Hope that helps

Cheers
RustyNCA

[RustyNCa]

Ok..... I've done some searching here and found the link where I seen a MC from any Mustang with front discs and drum rears would work good in the 65 Tbirds with some modification to the strut town brace.

I found RustyNCa link where he shows Raybestos MC36251. I couldn't find anyplace that had that but we were able to find a MC from a a 68 Mustang with a 302. I measured it it's pretty much right at 7" total length.

The problem is I cant get the bracket that sits atop the strut tower on without hitting the MC. I doesn't look like that is an issue with his pictures. Has anyone else ran into this issue? I dont' wanna to just start grinding away because i'm concerned that the braces which I know need modified wouldn't work.

My next thought is did the PO change out the booster? it's about 6 1/2" deep from mount to mount... Any thoughts?

I Know pictures would help but I'm still without a camera.

TIA. ShowMeGuy

Didn't see that you were doing this, but yeah I didn't have any clearance issues with the shock tower portion of the brace.

[ShowMeGuy]

Well, in my case.....

We didn't run a combination proportioning valve to the M/C.

We didn't check piston size in old M/C vs new, we didn't see that as a concern.

The way we did it, all we changed in the system was the M/C and a small bit of tubing, was very little change to the system other than the dual reservoir so you shouldn't need to worry about the brake switch etc.

No residual valve, my understanding you only need to run those when your M/C is lower than your Wheel Cylinder's which isn't the case here.

Hope that helps

Cheers
RustyNCA

I got it installed and used a one man bleeder to get the lines bled but i was expecting a lot softer pedal than I had prior knowing there was air in the line. Doesn't feel like power brakes to me.. I'll probably try to have someone help me bleed the brakes again.
I don't know that my mom or sister could drive it as the pedal is pretty stout to push and get stoppage. Probably air in the lines but you alls thoughts?

BTW, I plumbed mine exactly like RustyNCa has in his pics...

ShowMeGuy

[RustyNCa]

I got it installed and used a one man bleeder to get the lines bled but i was expecting a lot softer pedal than I had prior knowing there was air in the line. Doesn't feel like power brakes to me.. I'll probably try to have someone help me bleed the brakes again.
I don't know that my mom or sister could drive it as the pedal is pretty stout to push and get stoppage. Probably air in the lines but you alls thoughts?

ShowMeGuy

Hmm, when you say it's pretty stout to push, do you mean pedal feel or to get the brakes to grab?

Did the brakes work well before you started? Was the pedal fine before the change?

Another thing to look at is if the depth on the M/C matches up correctly with the plunger on the booster. Is it also possible you have a gap in there that is using up a bunch of your pedal travel before you are even activating the master?

I can tell you I was very pleased at how well it worked for me. Pedal feels great, brakes are very good, everything works just like it was placed there by Ford originally.

Cheers
RustyNCA

[simplyconnected]

...Doesn't feel like power brakes to me... ...the pedal is pretty stout to push and get stoppage...

If you have a larger piston in your new M/C, the pedal will definately feel harder to brake (compared to the old M/C).

If you are running a disk/drum setup without a combination proportioning valve, your rear drums will lock up before the front disks can do their job. After installing a combination valve, I wanted even less rear brake, so I went down in wheel cylinder size in the rear drums (from 7/8" to 3/4" pistons). It worked well. The old wheel cylinders were shot, anyway... bleeders were frozen, and I was re-plumbing the system.

Some M/C's have a residual valve integrated. Some don't. Residual pressure does two things... it keeps about ten psi on the rear line so the pistons don't collapse too rapidly (which can introduce air around the cups), and it's supposed to keep the shoes closer to the drums. Self-adjusters keep the shoes close too, so you use either the valve or the adjusters.

I can't tell from your plumbing pictures, but the larger bowl in the M/C should go to the disk brakes, regardless of what brand M/C you use.

A 'hard' pedal can be caused by:
* Replacing with a larger piston M/C (I use 1" with power disks.)
* The rod between the booster and M/C is too tight, prohibiting the M/C from 'resetting' when you let off the pedal. (This is dangerous.)
* Your brake pedal rod is too tight. It needs a little 'jiggle'.
* Flex hoses have collapsed internally from old age.

At rest, the M/C reservoir ports should be 'open' to the brake lines, allowing fluid to go back into the reservoir as the wheel cylinders retract. If the M/C never retracts fully, the ports can't open and tremendous pressure remains on the brake lines.

Bleeding your brakes won't take the stiffness out. If you have air in your lines, the pedal will feel mushy. - Dave

[ShowMeGuy]

Hmm, when you say it's pretty stout to push, do you mean pedal feel or to get the brakes to grab?

***I mean pedal feel....

Did the brakes work well before you started? Was the pedal fine before the change?

***The brakes didn't work that good before.... So i figured why work on something that isn't safe IMO. The pedal feels the same as it did before with... hard.

Another thing to look at is if the depth on the M/C matches up correctly with the plunger on the booster. Is it also possible you have a gap in there that is using up a bunch of your pedal travel before you are even activating the master?

***I will check that out tonight.

[RustyNCa]

If you have a larger piston in your new M/C, the pedal will definitely feel harder to brake (compared to the old M/C).

Makes sense, I would assume that my friend that got me the M/C must have taken that into consideration, he runs a business that specializes in brakes and alignments so I just went with the M/C he got me


If you are running a disk/drum setup without a combination proportioning valve, your rear drums will lock up before the front disks can do their job. After installing a combination valve, I wanted even less rear brake, so I went down in wheel cylinder size in the rear drums (from 7/8" to 3/4" pistons). It worked well. The old wheel cylinders were shot, anyway... bleeders were frozen, and I was re-plumbing the system.

Wouldn't the 65 which came with disc/drum from the factory already have a proportioning valve in place? And I would assume if the car already had a proportioning you would need to remove that one to run a different one on the car? Or in this case is showmeguy not dealing with a 65/66 car?

Some M/C's have a residual valve integrated. Some don't. Residual pressure does two things... it keeps about ten psi on the rear line so the pistons don't collapse too rapidly (which can introduce air around the cups), and it's supposed to keep the shoes closer to the drums. Self-adjusters keep the shoes close too, so you use either the valve or the adjusters.

Hmm, that would explain an issue a friend has on his model a that he removed the residual valves on. I am running them on my model a, but that was because I understood and was told you needed them only with the master mounted to low in the system.

I can't tell from your plumbing pictures, but the larger bowl in the M/C should go to the disk brakes, regardless of what brand M/C you use.

Yes, the larger bowl is going to the front discs

Bleeding your brakes won't take the stiffness out. If you have air in your lines, the pedal will feel mushy.

That was what I was thinking

[ShowMeGuy]

I'm running the stock proportioning valve. MC front chamber down the Proportioning valve and back to the drum rears. The front discs are split at a TEE on the larger chamber.
I'll try to look at your comments and reply with what I find tonight..
TIA guys!!
ShowMeGuy

[RustyNCa]

Hmm, when you say it's pretty stout to push, do you mean pedal feel or to get the brakes to grab?

***I mean pedal feel....

Did the brakes work well before you started? Was the pedal fine before the change?

***The brakes didn't work that good before.... So i figured why work on something that isn't safe IMO. The pedal feels the same as it did before with... hard.

Another thing to look at is if the depth on the M/C matches up correctly with the plunger on the booster. Is it also possible you have a gap in there that is using up a bunch of your pedal travel before you are even activating the master?

***I will check that out tonight.

Hmm, you might also want to take a look at your booster, could be it has quit working and take a hard look at all the lines, especially the soft connections. Those lines really aren't very costly for the role they have.

My brakes felt great, I had replaced the back brake cylinders because they had rusted all up, the front calipers were fine. Drove it that way for a few years and then one trip the back softline gave up and I lost all brakes, that is when I converted the car to the dual master and replaced all the rubber brake lines.