87 - 91 Master Cylinder mounted onto a 86 and older F-250 Diesel

[Old Goat]

Have any of you installed the later aluminum MC with the clear reservoir, to replace the old rusty cast iron MC?
There are several write up,s doing this, but mainly for the F-150 and Bronco`s.
I have several of those threads I saved that I have in a Folder.
Here is one of them.

'87 MC on an '85 Booster - Ford Truck Enthusiasts Forums

1987 - 1996 F150 & Larger F-Series Trucks - '87 MC on an '85 Booster - I'm copying this post from the 80-86 Bullnose forum to see if I can get any traction over here. I also have it posted in the brakes forum. Let me know if I should gut the Proportioning pressure regulating control valve Join...

www.ford-trucks.com

I posted this thread May 28, when I noticed the Brake peddle getting soft, and
searching noticed the frame wet from a leak. It looked like coming from the block
area where the 2 front and rear lines connect.

Soft Brakes, front 1/2 of MC low, leaky steel brake line

There are a 1000 threads on leaky brake lines. Been searching for the past hour on Google, different wording to find what Iam looking for. This past week the Brake Peddle suddenly started to get soft and low, but truck stops...ok. I have had the truck parked the past 6 days doing some other...

www.oilburners.net

I had to put this on hold as I had cataract surgery, and trying to do what the DR
said and be a good boy.

Yesterday I was under the truck poking around and notice now Brake Fluid running
down the edge of the inner Plastic Fender and dripping on the ground.
Now this is new.
I have had to add a little fluid to the front section of the MC about once a week.

I notice now the leak is between the MC and Booster.
Iam just hoping it isn`t going into the Booster.

Reading several threads on the swap to the newer style, the lines going into the
MC need to be reversed, and an adapter for the rear hole that can be gutted.
When I read about this swap couple yrs back, I grabbed a couple at PNP, and there
out in the shop some where.

So with all this long winded thesis, any of you done this swap on a 250 or 350?


Goat

 

[Clb]

I aint got much knowledge about this....
But check the 4 mounting studs for the booster. And m.c. stud spacing, and compare.
Doing hydroboost, that was the biggest thing.
Flare nut being second

 

[Old Goat]

Thanks.

Iam thinking tomorrow I`ll swing by O`Really`s and get the 86
Booster, and see how the 89+ Master lines up with the Studs.

I found the adapters I got at PNP a couple years back. Surprised
myself in all my unorganized schtuff in the shop, they were almost
looking right at me.Just need to take one apart and degut it.

9 years ago this month we bought the truck, and put 148K miles on
it. think this is the 4th time replacing the Booster and or MC.
Have had more trouble with brakes with this thing, than any vehicle
I have ever owned.


Goat

 

[chillman88]

Why not just upgrade to the larger booster that came on the newer trucks as well? I can't remember what year it came out. Some of the early trucks had a really thin booster.

Maybe it was in the early 80s it was upgraded but I really don't recall. I'd have to look it up. I seem to think it was a bricknose change though.

 

[KansasIDI]

Why not just upgrade to the larger booster that came on the newer trucks as well? I can't remember what year it came out. Some of the early trucks had a really thin booster.

Maybe it was in the early 80s it was upgraded but I really don't recall. I'd have to look it up. I seem to think it was a bricknose change though.

My 86 has the same size booster as my 90. Different master cylinder though

 

[chillman88]

My 86 has the same size booster as my 90. Different master cylinder though

Maybe it was earlier then. I'll have to look it up, I just remember there was a change somewhere in there. Might have been early 90s though.

EDIT: Now I'm not sure after a little google searching. There definitely was a TSB but that was for pedal droop. It may have just been the difference in GVW between the Under 8500# and the over 8500# trucks that I was thinking about. I know the spare booster I had pulled off an 88 was half the size of the booster on my 90.

 

[Old Goat]

The last guy posted this in the link I posted above.

"Coach I did this on my old 86. It’s a cinch. Get about a 87 F-250 or 350 plastic MC and bolt that sucker on. All I had to do was unscrew the 87 proportioning valve and remove its innards.

1-2 hour (beer) job. "

Also Master Cylinders from 87 - 91.

You will need this adapter from PNP or wreck, 87 or later

You must be registered for see images attach

You must be registered for see images attach

It`s 3 of these I got at PNP.

From another poster...

I'm running one of the 87-91 style master cylinders in my 1984 F150. It was a pretty straight forward install, but I was re-doing all of the brake lines at the same time.

You must be registered for see images attach

You must be registered for see images attach

The main reason I did the swap was to get rid of the rusty cast iron stock style master.

Details:

The front and rear brake ports are reversed from the stock master cylinder, so you will have to deal with that. (I was running new lines anyway, so NBD)
The rear residual pressure valve (attached to the master cylinder) does not come with a new master. I grabbed one at the Junkyard for $5 bucks (and a spare for another $5).
I removed the original Bullnose prop valve on the frame, and then connected the two wires to the float switch in the new master (so my brake warning light still functions). If you go to the junkyard to get a residual pressure valve, grab the float switch pigtail from the same truck.

Other than that, it works just fine. I've had it on there for a couple years now I think.
The piston is the same size as original, so braking power is the same.
The later master fits the Bullnose booster just fine. (Although I did adjust the push-rod tip a little bit)


I stopped at O`Really,s this afternoon
and picked up a Master Cylinder for a 89 F-250 8500 GVW,
NMC 11104, brand new, made in where else...china.
$79.99 + tax.

https://www.oreillyauto.com/search/v/a/5329/automotive-truck-1989-ford-f-250?q=nmc+11104

So tomorrow I`ll see how it fits, Just got home from the eye Dr., dilation and other drops to deaden the eye and the Lazer thing.
Should be good to go then.

Hope I posted something good here. Some how I got that one copied picture twice.

The Booster on my 86 F-250 in part# 54-73355, O`Really part #.
I have this written on the under side of the Hood for reference.
Last summer gave the pimple faced kid all the info for the truck.
Get home, larger diameter and I think a bit thicker, would not fit,
plus the 4 studs on the back did not line up with the 4 FW holes.

So if you are thinking of going to a different year, do your
measurements.



Goat

 

[Clb]

Fwiw
My 93 is a dedicated towpig.

Best thing I did was hydroboost.
I'm NEVER replacing a vacuum booster again if a conversion is available.
But cheap and good nuff is different.

 

[Old Goat]

Down the road, maybe a Hydroboost, just haven`t come across one.
Right now just need to keep the truck running...and stopping.

This afternoon I took the three adapters apart and gutted them, pretty simple to do. Think I used a 7/8" to loosen the 2 halves. Put adapter in the Vice to hold it,
pull the parts out, blew them out with Carb Cleaner and screwed them back together.


Goat

 

[Rdnck84_03]

I recently put a new master cylinder on my 84 f150 from O'Reilly that looks like the original style but made of aluminum.

James.

 

[Old Goat]

I posted in the "What did you do to your truck today"
Iam going to copy and post what I did so far, on last Fri/Sat.



Friday Iam under the truck, and notice fluid running down the edge of the inner plastic Fender. The MC is leaking between it and the Booster...great.

Ok, now I guess I have to dive into this mod.
Picked up a new MC for 87 - 91, and Booster for the 86.
The holes on the MC are not quite wide enough to fit onto the 86 studs.
Had to file them out on ea side to slide on to fit.
Bench bled the MC, and installed it.
The rear port on the later trucks use an special valve adapter. Took it apart, gutted it and installed it. Bought a bushing for front port.
Will need to reverse the 2 brake lines.
OH great, the threads are different, won`t screw in.

No problem, I`ll make 2 new Brake Lines.
removed front wheel, Battery and tray. Coolant Bottle and inner plastic fender.
Now I can get to where they connect to the distribution block.
Another "OH Great" they are so rusty they look to be one piece, and afraid they will twist off.


Did some Googling and it is the Proportioning Valve. didn`t know I had one.

You must be registered for see images attach

https://shop.broncograveyard.com/Disk-Disk-Pro-Valve/productinfo/22519D/


So will be here this week some time.
This is as far as I got on this project. Truck is down for a bit.

Really happy I dug into this, as I didn`t know the rust at the block.
All the other Brake lines are not rusty. best to get this fixed, and not when Iam knee deep in snow.

Tomorrow Iam headed to PNP and grab every Brake Line fitting I can find.
NAPA and O`Really`s don`t have much of an inventory.

OK now today... Monday.

Headed to PNP and grabbed about every threaded fitting for this
87 - 91 MC. Some you are going to by pass as were rusty and or rounded off.
Used my Bolt cutters to whack off the brake line. So tomorrow use my thin cut off wheel, and probably de-bur them to slide out of the fittings. Then degrease and wire wheel to clean them up.

Post#7 has a picture of the front and rear fittings you need, plus the Adapter.
Just whack off the line with your Bolt cutter, and remove with a 7/8". then at home separate them. It`s a 7/16 line Wrench for the small fitting.
The large front fitting is a 5/8".

Once you whack off the Brake line, if you don`t have a line Wrench, a Box Wrench will work. Don`t use an Open End or Crescent Wrench, good way to round off the fittings.


I forgot to bring a 7/8" wrench to remove the Adapter Fittings. Was going to grab a few just...because.


Goat

​

 

[Old Goat]

I just realized I never finished this thread, hate it when reading a thread and never the final act.

Iam not going back and reread the whole thread,
But to install the later MC on a 86 (in my case) you can use the stock Booster, but will need to file out the hole`s on each side so it fits onto the Booster. Not a whole lot.
It slides on and bolts up. Did need to readjust the Booster rod.

Old MC front section is for the rear brakes, and newer MC front is for the front brakes, so the 2 lines need to be swapped around. You can bend them around to line up, or just make new one`s as I did with the copper/nickel brake line.

Used the old fittings that connect to the Proportional Valve, but the fittings on the new MC are a bigger size, as mentioned above, and sourced them from PNP.
The rear one which is a valve, gutted the parts out of it, and screwed it in.

Remember you will need to do a double flair on the Brake lines, just remember to put the fitting on before doing it and correct direction.

Bench blead the MC, gravity blead the lines before attaching to the P Valve.
Had my Wife hit the Brakes, and the Valve adaptor on the rear of the MC leaked. Has an "O" Ring, but being 20" years old, guess it doesn`t take well to be messed with. Looks to be some special Ford ring.
JB Welded the 2 1/2`s together. Next day, applied and it was peeing a small stream....GRRR.

Had 3 of them, and took one to my welder friend and had him TIG weld it. All good now, no leaks.

Any one doing this project, it isn`t all that difficult to do now that I have done it. Looks a lot cleaner than the old rusty 10lb leaky MC.

I used this flaring tool by Lisle, works great.
I did use a C Clamp to hold it to my work bench once I had the Brake line set to depth and tightened down. Just made it easer to screw into the fitting to do the Double flair.

Lisle 33260 Flaring Tool

Buy Lisle 33260 Flaring Tool with an everyday low price and fast shipping! JB Tools

www.jbtools.com

Goat

 

[Old Goat]

I have been driving this thing for a good 6 months now, and the Brakes have never worked so well. I read hydro boost is better, but haven`t come across one yet.

I replaced the proportional valve and think it can be a problem as the rubber "O"Rings and other rubber parts after 38 years eventually deteriorate.
Here is another thread I did that should be tied in with this one about the proportional valve etc...

Hope it helps some one down the road doing a search.

Proportional Valve and MC leaking Brake Fluid

I started another Thread of a soft peddle and leaky Brake Line. Was never a big leak, just some slow drips. MC never ran dry, but low peddle etc... thread went to 4 pages, and sort of drifted off... https://www.oilburners.net/threads/soft-brakes-front-1-2-of-mc-low-leaky-steel-brake-line.92520/...

www.oilburners.net

Goat