Members with 4 wheel disc systems.....Can you get the tires to skid?

[Kern Dog]

I left the master cylinder attached to the lines. I’m still unsure if I’ll keep this unit or buy that cool looking 1 1/32” factory looking aluminum one.
I do know I’ll need to reposition this clutch master reservoir again.

The booster:

 

[Kern Dog]

I am having a pisser of a time with this.
My strength and tolerance with my arms over my head are still not back to normal since my roof fall two months ago. My arms get tired easily. The drop light never seems to aim the light at the right spot either. it is either at my face or shining on something I don't need to see.
I have not done this swap before. The car was originally equipped with manual drums.

The plate to the left is original. The one to the right is new. I should have placed the new over the old to show where obstacles would be. I found out the hard way that the snout on the back of the booster does not fit right into the firewall hole. The firewall hole for manual drum cars was narrow and ovalled, not round. I had to hog out the hole to get the booster to fit.

Also….
I found out the hard way that the under dash linkage has to be installed on the booster THEN the booster slid into place. I first tried to install the linkage under the dash but immediately saw that it would be extremely difficult to bolt it to the booster pushrod with all the obstacles in there.

I got 3 of the 4 booster bolts nutted down. The remaining one is the upper left as seen from the drivers seat. Of course, it is the hardest to see and access. If I had better lighting, it would really help. The shop isn't as light inside as I'd prefer and these drop lights just don't project enough light for me to see well. At junkyards and my own cars out in the yard, I can see under the dash just fine. OLD eyes, I guess....

 

[Kern Dog]

Force 10 brakes has this aluminum master cylinder....

Seems like a good deal. Factory appearance but 1/3 the weight.
I also may change the brake pedal. This is one that I modified for extra leverage.

The top one has a pushrod hole I drilled about 3/8" higher to increase the leverage. This power setup uses a reduction linkage. I'm curious if the higher pushrod hole could maybe damage the booster since it is no longer square.
I might be worrying for nothing. It won't take too much time to swap pedals. I actually had the lower pedal in place when I first swapped in this Tremec transmission 2 years ago.

 

[Mackman]

I had your same difficulties installing that booster in my 69GTX. I believe I have a deepwell socket ground very thin to access one fastener.

 

[Fran Blacker]

Tape around a u-joint to keep it from flopping around and a 12" extension. Mackman's deep socket.

 

[4406bbl]

I had your same difficulties installing that booster in my 69GTX. I believe I have a deepwell socket ground very thin to access one fastener.

Yes you need a mid depth socket like an s&k, 1/4" drive or ground down 3/8" and it still sucks to do.

 

[Sixpactogo]

The plate to the left is original. The one to the right is new. I should have placed the new over the old to show where obstacles would be. I found out the hard way that the snout on the back of the booster does not fit right into the firewall hole. The firewall hole for manual drum cars was narrow and ovalled, not round. I had to hog out the hole to get the booster to fit.

The factory dual diaphragm booster had a smaller boot on it and the China built ones have a larger boot. That is why you had to hog out the firewall a bit.
As far as that upper nut install, I found using a 3/8 drive long barrel socket with long extension worked great for me. I have a universal knuckle with spring that I bought years ago. Not sure where but it is the cats meow when you need a Universal. The guy that designed it has to be a master mechanic and should be a millionaire. I agree with you though on the issues with fumbling around under the dash as we get older and less agile. Anyway, Here is a pic of my go-to universal when I need one. Also, I think you will be happy with the extra boost too!

 

[1 Wild R/T]

 

[Kern Dog]

I’m on a cruise today with the car club. We are checking out wineries and other things along the Sacramento River.

 

[1 Wild R/T]

I’m on a cruise today with the car club. We are checking out wineries and other things along the Sacramento River.

The Old Sugar Mill?

 

[Kern Dog]

Scribner was one of them, I don't recall the names of the others. I don't drink much and rarely drink wine. I was there for the car guy interaction. The club President invited the Sacramento Mustang club too so we got a few more people than usual.
One guy had exhaust cutouts on his Mustang and REALLY liked running open exhaust. I usually like a loud car but that was obnoxious like a fart canned Honda.

 

[1 Wild R/T]

The Old Sugar Mill.. In Clarksburg, along the river... Bunch of Wineries & shops... Kept all the women & wine drinkers happy... I was happy just to be out for a drive.. This was Oct 2020 so just getting a group together & out on the road was cool... You can see how few people were out doing stuff..

 

[Kern Dog]

I have seen that. Impressive.
It is so beautiful along the river. There are some really nice houses there too.

 

[1 Wild R/T]

I have seen that. Impressive.
It is so beautiful along the river. There are some really nice houses there too.

Yup, done a few drives around the Delta... Lots to see...

 

[Kern Dog]

The swap is done. Sort of.
I did change the brake pedal back to the stock type....no offset pushrod hole. In retrospect, it probably wouldn't have hurt anything given the convoluted reduction linkage in the power arrangement. This of course required removal of the left cowl vent.
I'm not fond of how low the pedal sits.

It is at least 1 1/4" lower than the clutch pedal. If this was still an automatic, it wouldn't bother me. I might see if I can adjust the clutch linkage to lower the clutch pedal to get these two closer.
I started the car and the pedal went to the floor and stayed there. I suspect that it is because of the "busy" booster/4 to 2 adapter/2 bolt master cylinder setup.

I wonder if the master cylinder piston is just too far forward and if the booster pushrod is long enough to take up the slack.

I tried backing out the screw but man, these tiny nuts/screws are tight!

I suspected that I might have to go back to a traditional 4 bolt master cylinder to make this work so I ordered this:

I was hoping to drive today. I do have other 4 bolt master cylinders that I could temporarily swap in but I'm not sure I want to swap master cylinders several times, bleeding the system with this friggin expensive DOT 5 every time...

 

[Kern Dog]

Alright…
I’m retired and the wife is out of town so the heck with it… I went back out and tinkered some more.
I put in an iron 4 bolt master cylinder given to me by a forum member that owns this fine car:

It is a 15/16” unit. He didn’t like it and went with a larger bore.
I bench bled it and bolted it on. There is still air in the lines but I was interested in testing.
The pedal went down, not quite to the floor but it stayed.
Now… here comes a situation where blame could be placed in a couple of places.
The booster and linkage came with no instructions at all. I bolted up everything snug. I have never installed this B body linkage before.
The pedal was stiff and hard to move because the pedal linkage needs to have some slack in the pivot points. In my opinion, something as simple as a single page of instructions should be included for people that are unfamiliar with this setup. Dr Diff sells great parts at fair prices but he is like a lot of other vendors that don’t provide any instructions with their products. Some like Bergman Auto Craft do direct buyers to his website to download the instructions but even that annoys me. What are they saving per customer by leaving out a few pages? A dollar? Two bucks? Screw it, I’ll pay a few extra bucks for some decent guidelines.
With this 15/16” unit in place, even with some air in the system, it was immediately evident that this was an improvement. Pedal feel is much better. Pressing harder on the pedal gets more braking force. It slows enough now to stall the engine… a problem that I thought I had fixed by lowering the front float level.
I was able to skid on dirt but could barely skid the right front on pavement. At this point, if it stops this great but does not skid, I may be satisfied for now. Hard braking brings the confidence I have in the wife’s 2015 Challenger.
There are still a few details to tend to.
The brake pedal pad won’t stay on.

I have had trouble with it since it was new in 2021 when I swapped in the 5 speed. The difference in pedal heights is annoying. I am still considering the adjustment to the clutch linkage. Finally… the stalling while stopping issue needs more attention.
One last thing:
Vacuum pumps do work but repeated hard braking does deplete the supply momentarily. It sure would be great to not need the pump.

 

[hunt2elk]

I had stalling issues on one of my cars because of to high of float level in the rear bowl. Does your carb have those black plastic pieces at the top of the bowls to help prevent this issue as well?

 

[Kern Dog]

The front metering block is a Quick Fuel with that extended plastic piece. The rear is original for this Demon carburetor.
It doesn't stall every time but enough to be annoying.
I adjusted the floats months ago and thought I had this fixed. BACK to the old drawing board....

 

[68 Sport Satellite]

what was the bore size of the MC you had on there before swapping in the Raybestos Blue 15/16" MC? With your 4 wheel discs, that 15/16" should be the ideal bore size from what I've read.

 

[Kern Dog]

The aluminum 2 bolt MC I had was also 15/16". This allowed a direct comparison between boosters.
The only difference is that I now have a dual diaphragm booster. The car flat out stops.
I put on the iron 15/16" unit because it was right here on the shelf. It will not stay on the car though. I'll save it for the manual brake cars.
I bought the 1 1/32" aluminum MC that may arrive before the weekend, maybe not. When it does arrive, I'll install it and bleed out all the air. At that point, I may be satisfied enough to call this segment DONE.
I need a better quality brake pedal pad, one that actually stays in place.