My First Project - New Brake MC & Booster

Hello all! Just a small amount of background intro, skip to ::roject::: if you care not to read.

This is my first "project" car (1971 Mustang Conv.) and my first car that is older than 1991 for me to work on. I did not grow up with anyone to teach me cars, so really just been learning on my own/reading/watching as much as possible on the internet. However you can watch 100 videos and your application might be slightly different and sometimes you just need to know the "feeling" of how something works. So, this is a learning experiencing through-and-through. Whether this was the good first car to do it in, no idea, but it's a car that I always wanted and I finally have the adult money and time to do it. So bought the car late June and off we go!


::roject:::

Since about the second week of having the car, there has been brake fluid leaking underneath the engine bay, under the MC/Booster. So after reading some reviews, decided on the Leed's 9" MC & Power Booster kit as I read online that fluid leaking between the connection could ruin the booster seals and cause it to fail. So might as well replace both.


First was disconnecting the pedal brake light and the bolt. Easy enough for this one, once I was able to squirm underneath. There is a half-rectangle paper-clip looking item that fell and but I could not figure out what it is. Does anyone know the name of it and how it goes back together? I think I might be able to "guess" from the picture, will have to try.




Next I emptied the fluid from the MC and carefully disconnected the lines. Unbolted the MC rather easily and out she came. I would say it definitely corroded and caused the leak!





After that, I had struggled with unbolting the booster from inside the car. The top right one was rather difficult for me to position, but eventually was able to get it out. I am glad I got the kit with the new booster, does not look very good from the corrosion either.



That's it for now. I am waiting to get my bench vice installed so I can bleed the MC on it. Saw other places that showed other ways to do it, however the bench bleed seems more "formal" and I want to get it right for my first attempt.

Do you guys torque the bolts for the MC to the booster? I looked through the shop manual and I didn't really see anything mentioned. Some places online suggested 15-20 ftlbs, but I am unsure how as a regular ratchet was difficult to get the bolts on/off, let alone a torque wrench. I figured a feeling of "tight snug" would work.

Greetings. I don't 'torque' the MC nuts to a specific value. I just get tthem 'tight'.

I have always found the booster job to be much easier if I remove the driver seat. it only takes a few seconds to remove the seat.

When I install a MC I don't tighten it down until I have the brake lines connected and 'finger tight'. Being able to move the MC a bit will make it easier to get the brake lines started, it's something i always struggle with.

A lot of 'rebuilt' MC have the same size threads for the front and rear brake lines. I am going from memory but I believe it is our mustangs that have different size fittings for the front/rear lines. Check to make sure you have everything you need before you start assembly.

PUT A LOT OF RAGS BELOW THE MC. You'll leak brake fluid and the stuff will eat through paint. Cover the fenders too.

I tossed in 'speed bleeders'. This makes bleeding the brakes much easier for one person.

I think that retainer chip is part of the brake stop switch. Been a long time but I think it retracts along with spring. Or it holds it place with some other clips.

Update: It does look like some jury rig.

Congratulations on taking this on yourself! These are great cars to learn the basic mechanic skills on. If you haven't already, buy yourself a set of Ford Service Manuals for your model year. These are much better than the all-in-one Chilton manuals. You can get these digitally or hard copy - I prefer to have both. The manuals are well organized and do a good job walking you through the repair processes.

I've not seen the metal piece between the brake light switch and the push rod before. It may be something some previous owner/mechanic placed to get the brake lights to work properly. There are different brake light switches for power and manual brakes. May want to verify you have the correct one for power brakes.

The manual calls for 13 - 25 ft. lbs for the MC to booster nuts, but Will e above got it right - just get them tight.

cv_72mustang said:

I think that retainer chip is part of the brake stop switch. Been a long time but I think it retracts along with spring. Or it holds it place with some other clips.

Update: It does look like some jury rig.

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Yep I confirmed with the shop manual, there is suppose to be some sort of bushing in there (I did not have such circular bushing). Perhaps whomever converted this car to disc brakes lost it and used the clip.

Well I got the new booster bolted in and the brake pedal assembly (old style) back together. Pressed the pedal and....the brake light stays on. I loosened and tightened, both ended in the same results: 1-3 pedal depresses and the brake lights stay on.

Leed's kit did include the bolt and bushing (no pin, have to buy that) and will try and see if that fixes the issue. I could have also broken the switch? Any other thoughts? If anyone has a picture of their assembly, I would appreciate it.

will e said:

Greetings. I don't 'torque' the MC nuts to a specific value. I just get tthem 'tight'.

I have always found the booster job to be much easier if I remove the driver seat. it only takes a few seconds to remove the seat.

When I install a MC I don't tighten it down until I have the brake lines connected and 'finger tight'. Being able to move the MC a bit will make it easier to get the brake lines started, it's something i always struggle with.

A lot of 'rebuilt' MC have the same size threads for the front and rear brake lines. I am going from memory but I believe it is our mustangs that have different size fittings for the front/rear lines. Check to make sure you have everything you need before you start assembly.

PUT A LOT OF RAGS BELOW THE MC. You'll leak brake fluid and the stuff will eat through paint. Cover the fenders too.

I tossed in 'speed bleeders'. This makes bleeding the brakes much easier for one person.

Click to expand...

as easy as it is to pull the steering wheel, I recommend that as well - ultimately, to each their own . . .

There's been some "rigging" going on with your brake pedal setup. The manual and power brake switches are different part numbers. IIRC, the difference is in the spring rate. That "square-U" thing looks like they were using it as a shim.





I'm willing to bet that the bolt was added by whomever converted the car, and they just modified the original manual brake pedal. Looks like I can see the pin for the manual master cylinder. It mounted through the top two holes that the booster studs now occupy.

Many of the power brake conversion kits, (very good one), do just that. Relocate the push-rod location on the original manual brake pedal. nothing wrong with that, if you know how to use a drill, it saves you a good bit of money as well.

Hemikiller said:

There's been some "rigging" going on with your brake pedal setup. The manual and power brake switches are different part numbers. IIRC, the difference is in the spring rate. That "square-U" thing looks like they were using it as a shim.


View attachment 92536


I'm willing to bet that the bolt was added by whomever converted the car, and they just modified the original manual brake pedal. Looks like I can see the pin for the manual master cylinder. It mounted through the top two holes that the booster studs now occupy.


View attachment 92535

Click to expand...

Not sure if I can tell what the arrow is pointing to, but I looked and didn't see anything notable there. I can take more pictures?


Update 9/2:

I do not have the correct bolt pin, so that idea went out the window. Further attempting to position the brake switch & shim with the booster rod gave the same issue.

New issue is now the right brake light no longer comes on, so I guess I must have hit something or damaged the switch by accident, not surprised as there was a lot of jostling.

I ordered two switches: one for power and one not just to see which one might work as I have no idea what switch I have now and some other comments online have said non-power worked better for their powered brakes. They are cheap so no biggie on that.

I wanted to go ahead and installed the MC, but thought it would be better to wait in case I need to remove and re-install the booster. I have a feeling I didn't do it right and there is a slight tilt, not sure.

Decided not to give up tonight, still had some energy.


Uninstalled and re-installed the booster. Seemed to line up really well and installed the stuff (without shim) and it somewhat worked. Tightened/loosened whenever the light cut out but just could not get it to work 100%.

Then re-installed it with the shim, tightened/loosened for the light on/off and finally got it to work! I pumped the pedal probably 50 times and it came on and off as desired. Also the right brake light is back on, no idea why/how.


However now the turn signals don't work. The running lights and hazards operate as normal, but left and right signals, nothing. No idea, perhaps I booped something while messing with all the brake stuff. Any starting places to look for an issue would be helpful.

Next I'll install the MC (after bench bleeding) and then bleed the brakes and hope for the best!

When turn signals don't work but 4 way flashers do, that's a good sign that your turn signal switch is bad.

midlife said:

When turn signals don't work but 4 way flashers do, that's a good sign that your turn signal switch is bad.

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Seems rather coincidental, but I suppose it could just be terrible timing.

I have the wiring diagram manual, still will chase it down and see if I can find any loose connection. I also could have easily bumped the fuses, as they are there and sitting in the open.

All in all the brake lights work, and I'm in Florida where turn signals are optional

Today's work 9/3:


Spent about 30 minutes bench bleeding the MC, probably too long as I didn't see bubbles for quite some time, but wanted to be sure. Installed MC to the booster, then torqued down the bolts (35ftlbs) and it's all set! While fluid came out of the holes while putting the brake lines back on, I made sure to never let the reservoir get empty. I tightened the brake lines down until they were very snug.




Next will be to bleed all the brakes, starting with pax rear. I thought I'd be able to do it with the car on the ground and the wheels on, but just not enough clearance (although close) so I will just raise the car up...I don't think I will need to take the wheels off. After that I think it should be good! Hopefully I didn't mess up anything, I feel quite nervous that I'll have to start all over lol.


After looking up the wiring diagram for the turn signal, I saw that it shared the same fuse as the radio. When I tested it the other night, I remember (while in accessory mode), that the radio wasn't on, or at least I thought so. I went under and removed, re-set the fuse and tested: worked!

All coming along, I think!

Seems to be coming together for you! You were right to bleed the MC, then bleed it some more. It can be a challenge to get all the air out of an MC.

sevian87 said:

Today's work 9/3:


Spent about 30 minutes bench bleeding the MC, probably too long as I didn't see bubbles for quite some time, but wanted to be sure. Installed MC to the booster, then torqued down the bolts (35ftlbs) and it's all set! While fluid came out of the holes while putting the brake lines back on, I made sure to never let the reservoir get empty. I tightened the brake lines down until they were very snug.


View attachment 92665

Next will be to bleed all the brakes, starting with pax rear. I thought I'd be able to do it with the car on the ground and the wheels on, but just not enough clearance (although close) so I will just raise the car up...I don't think I will need to take the wheels off. After that I think it should be good! Hopefully I didn't mess up anything, I feel quite nervous that I'll have to start all over lol.


After looking up the wiring diagram for the turn signal, I saw that it shared the same fuse as the radio. When I tested it the other night, I remember (while in accessory mode), that the radio wasn't on, or at least I thought so. I went under and removed, re-set the fuse and tested: worked!

All coming along, I think!

Click to expand...

You said this car has a disc brake conversion? I hate to tell you this, after all the nice plumbing you've done, but you need to replace your combination valve. Drum brake valves are designed differently than disc/ drum or disc/ disc. MP brakes has nice units available with easy to use instructions & bracketry that allows you to mount it directly under the MC, even comes w/ the pre-bent lines from the mast to the valve.

canook2u said:

You said this car has a disc brake conversion? I hate to tell you this, after all the nice plumbing you've done, but you need to replace your combination valve. Drum brake valves are designed differently than disc/ drum or disc/ disc. MP brakes has nice units available with easy to use instructions & bracketry that allows you to mount it directly under the MC, even comes w/ the pre-bent lines from the mast to the valve.

Click to expand...

I've never heard of such a thing, didn't see anything that said it needed it, so this is new.

I believe it has one already of sorts (will have to check), there are brake lines from the MC that goes to a block of sorts. The brakes were never in bad shape, they stopped fine, just was leaking between the seal. I still have to replace this valve?