My 1984 F150 2wd Flareside Project "Blue Mule"

[Rembrant]

So back to the topic of the thread...

Which one did you NOT get a picture of? Was it the little red 2-wire SCDS, or the big cast 4-wire RABS valve?

I did not see one of the frame mounted SCDS units at all. The first truck I looked at, the one I was asking about the unknown device on the frame, had the big RABS valve. Since you said it was the 1993 only frame mounted SCDS, I took that information and walked away. Had I actually looked at your picture...LOL, I would have known immediately that what I saw wasn't the SCDS. It only occurred to me later, after looking at a couple more trucks, that what I was asking about couldn't have been the SCDS.

When you said that we weren't looking at all of your pictures, you were right...lol.

By the way, that RABS valve is well hidden inside the frame rail. The wiring is not easily visible, and after 25 years of dirt, oil, and rust, all you can really see is a brake line going inside the frame, and a brake line coming out, that's it. I assume it is just a servo driven piston affair that releases rear brake line pressure when the ECM senses the rear wheels locking up before the fronts?

In any case, at least I know what it is now, and I have most of my new braking components ready to roll.

NOW...next question...

I looked in my 1984 FSM and did not see a spec on adjusting the booster rod. Mine seems to have a fairly large gap (like, in the area of 0.060" from my measurements). I found a generic spec that it should be more like 0.005", but that wasn't specific to Ford. Do you guys adjust these, or should there be a bit of a gap anyway?

 

[Gary Lewis]

So back to the topic of the thread...

Which one did you NOT get a picture of? Was it the little red 2-wire SCDS, or the big cast 4-wire RABS valve?

I did not see one of the frame mounted SCDS units at all. The first truck I looked at, the one I was asking about the unknown device on the frame, had the big RABS valve. Since you said it was the 1993 only frame mounted SCDS, I took that information and walked away. Had I actually looked at your picture...LOL, I would have known immediately that what I saw wasn't the SCDS. It only occurred to me later, after looking at a couple more trucks, that what I was asking about couldn't have been the SCDS.

When you said that we weren't looking at all of your pictures, you were right...lol.

By the way, that RABS valve is well hidden inside the frame rail. The wiring is not easily visible, and after 25 years of dirt, oil, and rust, all you can really see is a brake line going inside the frame, and a brake line coming out, that's it. I assume it is just a servo driven piston affair that releases rear brake line pressure when the ECM senses the rear wheels locking up before the fronts?

In any case, at least I know what it is now, and I have most of my new braking components ready to roll.

NOW...next question...

I looked in my 1984 FSM and did not see a spec on adjusting the booster rod. Mine seems to have a fairly large gap (like, in the area of 0.060" from my measurements). I found a generic spec that it should be more like 0.005", but that wasn't specific to Ford. Do you guys adjust these, or should there be a bit of a gap anyway?

Cory - I have it documented here: Driveline/Brakes and on the Master Cyl's & Boosters tab and then the Push Rod Adjustment tab.

[Rembrant]

Cory - I have it documented here: Driveline/Brakes and on the Master Cyl's & Boosters tab and then the Push Rod Adjustment tab.

I guess I didn't do a very good job of searching for that Gary, assuming it is also in my 1984 FSM. My required measurements are a little different...I assume because I'm installing the later master cyl. I'll adjust it so that it just touches. No big deal. Thank you sir.

[Gary Lewis]

Cory - I have it documented here: Driveline/Brakes and on the Master Cyl's & Boosters tab and then the Push Rod Adjustment tab.

I guess I didn't do a very good job of searching for that Gary, assuming it is also in my 1984 FSM. My required measurements are a little different...I assume because I'm installing the later master cyl. I'll adjust it so that it just touches. No big deal. Thank you sir.

Be really careful with the adjustment. Scott/WelderScott and I adjusted his to just touch and when the brakes got warm they dragged and then got hot and then stopped the truck.

I would err on the side of a little bit of clearance.

[Steve83]

I assume it is just a servo driven piston affair...

No, just a spring-loaded piston in a brake-fluid-proof cylinder. But it's normally isolated from the brake line, so it normally does nothing.

...releases rear brake line pressure...

I wouldn't say "releases"; I'd say "stores fluid to reduce pressure".

...the ECM senses the rear wheels locking up...

"ECM" makes me think you're referring to the engine control. To avoid confusions, I only refer to it as the RABS module (later renamed RABS-II after a minor software improvement).

...before the fronts?

The front wheels are not monitored in any way. The module only observes the CHANGE in speed of the rear wheels, when that speed is above a certain threshold. If they slow too rapidly, the RABS assumes they're about to lock up, and dumps some fluid into the RABS valve on the frame. There's a 1-way valve that allows the spring to push that fluid back into the line (& up to the reservoir) when you let off the pedal. For more info, read this & the NEXT several captions:

https://supermotors.net/getfile/280872/thumbnail/rabs-components-92.jpg

...a spec on adjusting the booster rod.

https://supermotors.net/getfile/280792/thumbnail/brake-booster-adjustment.jpg

Do you guys adjust these...?

I never have, on any vehicle; even mine, after swapping MCs &/or boosters &/or pedals.

[Ferdinand]

...Motorcraft BRMC63 (#F4TZ2140E). I hadn't looked at this one previously because it was quite a bit more expensive than the others.

I certainly understand about price-shopping, but on things like brakes, I always try to consider that maybe it's WORTH more. Do you regularly check Amazon or Tasca for auto parts?

https://www.amazon.com/dp/B001CA76TU

https://www.tascaparts.com/oem-parts/ford-ford-bronco-master-cylinder-f4tz2140e

It's worth noting that this MC is for all '87-93 F150/Bronco, but not '94-96 w/cruise (front boss not drilled for the SCCDS). I haven't found a source for the Ford/MotorCraft '94-up cruise MC (F4TZ2140FA), but I think BRMC38 would work if you swapped the smaller reservoir on.

Steve thanks for the link of the Tasca Parts site! I hadn't heard of it yet.

Rembrant, I am following the braking upgrades...

I thought about trying the hydroboost set up a lot of folks seem to like, but I've heard good and bad either way, so I am staying stock for the time being.

Let me know what method you use to bleed your barking system. I bought one of those reverse bleeders from Phoenix systems and I am only somewhat impressed. The kit was $50, and I still ended up bleeding them the old fashioned way. (and alone no less, so that's always fun)

Keep peelin'

[Steve83]

...reverse bleeders from Phoenix systems...

Is it a vacuum bleeder? Reverse-bleeding doesn't require any equipment (and it's my preferred method). It's described in this caption:

https://supermotors.net/getfile/895333/thumbnail/mastercyl9496.jpg

I've used it on my truck, several similar trucks, my car & others, and modern 4WABS/TC vehicles while working at dealerships & independent shops. I've never had to do the 2nd part of the procedure.

[Rembrant]

Let me know what method you use to bleed your barking system. I bought one of those reverse bleeders from Phoenix systems and I am only somewhat impressed. The kit was $50, and I still ended up bleeding them the old fashioned way. (and alone no less, so that's always fun)

I have one of those motive power bleeders or whatever they're called (with the cap adapter for European cars...in my case, Volkswagens) and I was never able to get the thing to work properly. It's in the box on the shelf in my garage collecting dust.

Most of the time I use a power bleeder that I made years ago using an SMC vacuum ejector on a glass jar. It takes compressed air to run, but offers constant hands free adjustable vacuum. I usually stick in on a bleeder screw, turn the vacuum on, and then go and slowly pour the fluid in the reservoir. Once the bubbles stop coming out of the bleeder screw, I close the screw. If I pull the tube off the bleeder with the vacuum still on, I don't even get a single drip to wipe up.

I use it for other jobs too, but I made the thing originally for doing motorcycle brakes so I could bleed both front calipers at the same time.

 

[Gary Lewis]

Let me know what method you use to bleed your barking system. I bought one of those reverse bleeders from Phoenix systems and I am only somewhat impressed. The kit was $50, and I still ended up bleeding them the old fashioned way. (and alone no less, so that's always fun)

I have one of those motive power bleeders or whatever they're called (with the cap adapter for European cars...in my case, Volkswagens) and I was never able to get the thing to work properly. It's in the box on the shelf in my garage collecting dust.

Most of the time I use a power bleeder that I made years ago using an SMC vacuum ejector on a glass jar. It takes compressed air to run, but offers constant hands free adjustable vacuum. I usually stick in on a bleeder screw, turn the vacuum on, and then go and slowly pour the fluid in the reservoir. Once the bubbles stop coming out of the bleeder screw, I close the screw. If I pull the tube off the bleeder with the vacuum still on, I don't even get a single drip to wipe up.

I use it for other jobs too, but I made the thing originally for doing motorcycle brakes so I could bleed both front calipers at the same time.

I have a Mityvac with the accessories for bleeding brakes. But the threads of the bleeder screw leak such that you are never sure if the bubbles are from the threads or from the system. So I don't like using it.

My plan is to get one of the HF brake bleeder kits to use on the plastic reservoir of the later MC.

[Steve83]

But the threads of the bleeder screw leak such that you are never sure if the bubbles are from the threads or from the system.

Apply silicone dielectric/brake grease to the threads to seal them.

But it's moot with reverse-bleeding since the bleed screws aren't opened.