Rear Brake Conversion Advice

[Doc76]

Doc, are you changing the axles?. If not, any difference in width will be the difference between the drum and rotor axle flange face. Minimal if anything.

Norm

Thanks Norm
I presently have no plans to change the axles.
Sounds like it should work out but I’ll come back with an update after I’ve installed the kit.

[Doc76]

Hey guys just digging into this.
I was under the impression the adjustable Wilwood prop valve was plumbed into the rear line but in speaking to FFR they said to remove the OEM one (suggested here to gut and plug) and Wilwood adjustable valve actually gets plumbed into the front line.

Can anyone confirm that?

[Jeff Kleiner]

Hey guys just digging into this.
I was under the impression the adjustable Wilwood prop valve was plumbed into the rear line but in speaking to FFR they said to remove the OEM one (suggested here to gut and plug) and Wilwood adjustable valve actually gets plumbed into the front line.

Can anyone confirm that?

Well, since these cars almost always have too much front brake and not enough rear brake why would you want to put a prop valve in the rear to reduce the effectiveness even more...

Jeff

[Norm B]

Doc, the fox body V8 Mustang has a weight distribution of approximately 60/40 front/rear. Manufactures, for safety reasons, are always going to set their brake system to lock the front brakes before the rears in all conditions. The FFR roadster is very close to 50/50 weight distribution. Mustang brakes will always have too much front bias to achieve maximum stopping power when used on the roadster.
The question is, do you need maximum braking ability for how you intend to use the car? Are you going to be racing? Or, are you going to be driving friends and family around and want good, safe and reliable brakes?
If you mess around with brakes, without knowing exactly what you’re doing, you can create a very dangerous situation. Too much rear bias will cause the back end to come around and you will be looking back where you were coming from.


Norm

[GoDadGo]

Have you thought about possibly going with 1995 Ford Explorer Rear Brakes?
They use a Top Hat style brake rotor for the parking brake.
I've got them on my car and they work very well.
The diameter is just a bit over 11 inches.
I got my set up from Moser Engineering.

Check out Moser Engineering's OEM style rear brake systems shown below:

https://www.moserengineering.com/Par...rake-Kits.dept

[Doc76]

Front it is!

[Doc76]

Have you thought about possibly going with 1995 Ford Explorer Rear Brakes?
They use a Top Hat style brake rotor for the parking brake.
I've got them on my car and they work very well.
The diameter is just a bit over 11 inches.
I got my set up from Moser Engineering.

Check out Moser Engineering's OEM style rear brake systems shown below:

https://www.moserengineering.com/Par...rake-Kits.dept

Already have the rear FFR kit in the shop

[PG_Cobra]

Video from Master Power Brakes on brake combination valves: https://youtu.be/dD1dbNtH-6s

I have the MPB disc-disc combination valve installed.

[Doc76]

Video from Master Power Brakes on brake combination valves: https://youtu.be/dD1dbNtH-6s

I have the MPB disc-disc combination valve installed.

What’s interesting (and contributes to my confusion) with this video is this guy says to never install a prop valve in the front.

[PG_Cobra]

I have it installed with the prop valve to the rear brakes. According to MPB it only kicks in under severe braking to keep the rear end stable. It doesn't proportion the rear brakes at other times.
The function I really wanted was the safety shuttle so if I get a line failure I still have braking capability, somewhat reduced.

[Doc76]

I have it installed with the prop valve to the rear brakes. According to MPB it only kicks in under severe braking to keep the rear end stable. It doesn't proportion the rear brakes at other times.
The function I really wanted was the safety shuttle so if I get a line failure I still have braking capability, somewhat reduced.

Can you share a picture of the setup when able?

[PG_Cobra]

Picture attached

IMG_0480.jpg

I have removable panels for easy access. The MC is for a Chrysler New Yorker, 1"-ish (metric) bore with left hand ports. Just no room on a MK1 with booster to get the lines in on a Mustang MC with RH ports. Under floor exhaust so tons of room and no heat problems

[Doc76]

Doc, are you changing the axles?. If not, any difference in width will be the difference between the drum and rotor axle flange face. Minimal if anything.

Norm

I hadn’t planned but I wonder if this is a good time to upgrade to 31 spline while the rear is out and apart?

[Doc76]

Can I cut these brackets off to clean up the axles once pulled and welding or is there a chance they’re used for future mods?
Looks like the Moser axle doesn’t have them either.
IMG_0985.jpgIMG_0986.jpg

[Norm B]

Those brackets are for the quad shocks used with the Mustang 4 link suspension. You already have a 3 link setup so they can go.

Norm

[Doc76]

Took longer than I hoped but one last step to test fit the wheels to verify clearance and it’s all ready to strip.
That’s again to all those here that offered support
IMG_0999.jpgIMG_1001.jpgIMG_0988.jpgIMG_1002.jpg

Also, I see that my studs are now too short. Thank goodness I didn’t order axles yet. There a heavy 3/16” too short to the face of the nut.
Any recommendations on how long to lengthen them by without interfering with the trim ring?
IMG_1006.jpgIMG_1004.jpgIMG_1003.jpegIMG_1005.jpg

[Doc76]

Anyone have pictures they could share of how they routed the 20” SS rear brake line from the FFR conversion kit?
Seems the line is ~3” too long and the only way I can see they can work is to put a loop in the line. I get there need to be extra for axle drop. FFR said the lines used to be 17” but now they provide 20” front and rear.
IMG_1023.jpeg

Is there anything else I should look for before yanking everything back off for rear end removal?

[Flip Smiley]

Hey Doc on your rear axle stud length. Are you sure all the surfaces are clean and pulled completely flush. The stock axle stud should have 1.34” available length. The stack up, brake rotor, wheel and lug nut is approximately 1.34” loose fit before torque applied. You may have something interfering with allowing for flush draw up?
Just a thought?
Best regards.

[Doc76]

Hey Doc on your rear axle stud length. Are you sure all the surfaces are clean and pulled completely flush. The stock axle stud should have 1.34” available length. The stack up, brake rotor, wheel and lug nut is approximately 1.34” loose fit before torque applied. You may have something interfering with allowing for flush draw up?
Just a thought?
Best regards.

Hey Flip
Thanks for the feedback.
I just checked, off the axle face my studs are 1.325” and the rotor is ~.324”. When I mount the rotor and hold it to the axle face I have .978”. When I measure the face of the nut sitting in the wheel, to the back of the wheel face I get 1.193”. So those checks verify the studs on these axles are now ~1/4” too short just to the face of the nut. Couple that with the fact the first ~1/4” of the stud has no thread, I think I need studs 1/2” longer on my new axles.
Any feedback is appreciated

IMG_1029.jpg

[Flip Smiley]

OK good check. I’m not an engineer and don’t play one on TV. Maybe others with more knowledge in this area can chime in. When torqued to spec if the end of the stud is flush with the face of the nut that may be enough thread engagement? I know the studs are tapered with no thread on the end.
Many others have put these exact parts together with the same results. If there is a problem many others have the same issue.
Best regards Flip

[Doc76]

lol we call them pretengineers in my line of work.

I did a bunch more reading this.
From what I can tell the 1987-1993 era mustangs and explorers had longer studs on the axles than Aerostars which were also pillaged for the 5 lug conversions on many mustangs.
Not sure if this is possible.
I’ll call FFR this week.

[David Williamson]

you need longer studs, Press the old ones out and pull new ones in. The threads on the lug nuts should be fully engaged with the threads on the studs.
David W

[Jeff Kleiner]

Pretty simple really. The FFR rims which you have use open ended lug nuts. If the threads don’t come all the way through the studs are too short.

Jeff

[Norm B]

Doc, recommend you press a stud out and take it with you to the parts store. I bought some online that I thought were correct but my Moser SN95 conversion axles had a bigger knurled section where they pressed into the axle flange than the regular SN95 ones.
Got 10 longer replacement ones at Costco. Saw they had a vast assortment of studs while I was there getting winter tires for another vehicle. Apparently they brake a lot of studs.��

Norm

[Doc76]

Do any of you guys know how far the stud can stick past the nut face before interfering with the decorative cap held on by the spinner?

[rich grsc]

Thread engagement at minimum is equal to the diameter of the stud. So a 1/2" stud needs 1/2" of threads. Look at a bolt & nut, the nuts are rarely taller than the diameter of the bolt.

[Jeff Kleiner]

Do any of you guys know how far the stud can stick past the nut face before interfering with the decorative cap held on by the spinner?

Here's one that I have in here currently with FFR rims along with their supplied lug nuts and wheel studs. It could go farther, but why would you? As long as there are threads beyond the end of the nut there's no need.



Jeff

wheel stud.jpg

[Doc76]

Here's one that I have in here currently with FFR rims along with their supplied lug nuts and wheel studs. It could go farther, but why would you? As long as there are threads beyond the end of the nut there's no need.



Jeff

wheel stud.jpg

Perfect!
Thanks so much Jeff.
Looks like there lots of wiggle room

[Doc76]

Anyone have pictures they could share of how they routed the 20” SS rear brake line from the FFR conversion kit?
Seems the line is ~3” too long and the only way I can see they can work is to put a loop in the line. I get there need to be extra for axle drop. FFR said the lines used to be 17” but now they provide 20” front and rear.
IMG_1023.jpeg

Is there anything else I should look for before yanking everything back off for rear end removal?

Spoke to FFR today who said the 20” lines you just gotta kinda find a way to make them work so they don’t get hung up on anything. I plan to reassemble everything (axles are out now) to look at it again. If I install per the instructions, the lines are simply too long and look like they’ll rub on the tire. Rather than mounting the bracket vertically, facing out, I wonder if mounting it horizontally to promote the line dropping down is the way to go.
This is how Mark at Breeze suggested running the front lines to avoid a similar situation on the front 20” lines to avoid them rubbing when turning.

[Doc76]

Any good reason to not mount the rear brake line mounts behind the 3/4” tube instead of in front?
I had a hole on each side of the car on the inside of the 3/4” from the OB mounting straps so I thought I could plug the holes at the same time.
Also, the lines are no longer 17” and FFR’s kit comes with 20” lines front and rear so there’s a lot of excess line to take care of. I’m thinking it at least pushes the mount back 3/4”.
IMG_1445.jpg

[Doc76]

Has anyone mounted one of these Willwood adjustable proportional valves behind the drivers seat under the car so the black knob sits through the rear wall?
I was thinking it may be a good option to be able to reach it. (Ie just reaching around the seat with your right hand)
I am aware ill likely adjust it once and likely not again but I don't want to see it in the the cockpit, don't want to have the added complexity of the remote cable adjuster with big blue knob and mounting it in the engine bay is a little less "neat" looking IMO.
Seems to me if you have access to the underside of the car this would be a better option for reaching it on the fly and should a leak occur, its not dripping on/near headers, etc.
The only reason I can see this is not a good idea, and probably should be a big consideration, is the valve itself being much more exposed to the elements.
I am aware I may not need one but as good measure for the $50 I believe adding an adjustable valve now to be less work/time/$ than potentially later.

Attachment 208662

[rich grsc]

NO adjustable proportional valve. You've been given this advice before, listen to it. If you have $50 buck to throw away, just send it to me

[Doc76]

Doc, recommend you press a stud out and take it with you to the parts store. I bought some online that I thought were correct but my Moser SN95 conversion axles had a bigger knurled section where they pressed into the axle flange than the regular SN95 ones.
Got 10 longer replacement ones at Costco. Saw they had a vast assortment of studs while I was there getting winter tires for another vehicle. Apparently they brake a lot of studs.��

Norm

My 31-spline Moser axles came with the correct length studs. Yes, I am referring to the axles I had no plans to change lol Funny I couldn't find them locally.

[Doc76]

Looking for a little reassurance here. Before I start flaring I have a tool that does 45deg flares.
I called and asked FFR to be sure and they said the brake line fittings in their rear brake kit are all SAE 37deg standard flares however from what I see online the standard for SAE is in fact 45deg.
It looks like the AN fittings are 37deg.
Can anyone confirm?

Thanks

[Jeff Kleiner]

45 degree double flare on the hard lines. The AN fittings on the flex hoses are 37 degrees.

Jeff