89 Formula: How to go to manual brakes?
 

Hi guys,

Have an 89 WS6 Formula with the LS1 calipers and rotors from BigBrakeUpgrade in front, stock aluminum calipers in back.

This is a street / auto-x car.

Want to go to manual brakes to free up space for turbo setup and looking to remove the vac booster.

In researching here over the past few years threads I think I need

1. adapter plate
2. new pushrod
3. pushrod attached higher on pedal.

Does this sound right? Can I reuse my existing mc? I don't like the clip-on reserviour lid, would rather have a screw on like 4th gen mc so I'm looking to make that change.

Thanks for comments on this.

Re: 89 Formula: How to go to manual brakes?
 

Subscribed!
I'm too interested and for the same reasons; weight saving, space, etc and Solo1/AutoX/TrackTime.

I have the same upgrades as you with SS brake calipers and rotors, but I also did de 4th gen MC swap. It's basically a bolt on swap althouth I did had to make some small lines from the MC to the adjustable prop valve. I am not entirely certain, but for some reason I feel the car braking less aggressive, I am pretty sure the prop valve needs adjustment. Another guy told me at the track that it could be the MC's piston size that could be larger hence is heavier to brake, of this I am not sure.

Re: 89 Formula: How to go to manual brakes?
 

Jegs, & Summit sell a conversion kit with all the parts you need.

Strange Engineering sells the MC with smaller bore size which you will need if you only have single piston front calipers.

The Jegs and Summit kits have a big bore master cylinder which may be too big for your application. ( you will not have enough pressure for single piston calipers.)

I bought the Jegs kit and the smaller bore M/C from Strange, but when I convert the front to 2 or 4 piston calipers I have the big bore M/C that came with the Jegs kit in my spare parts cabinet.

A lot of guys that convert to manual brakes complain about the pedal feel. 99.9 % of the time they simply have the wrong size M/C for their application.

I have OEM style single piston front and Wilwood 2 piston rear the car stops just fine from 131 + MPH and I slow down nice, straight, & easy at the end of a run. no reason to jump on the brakes and panic stop.
street manners is just fine too.

Re: 89 Formula: How to go to manual brakes?
 

Thanks for that info 88!

BBS based on my research seems like you want to go down in bore size. Creates more pressure, moves less volume.

Both of these are > 1"

http://www.jegs.com/i/JEGS-Performan...ductId=1558862

http://www.summitracing.com/parts/bmr-mbk001/overview/

There's this one too, comes with a pushrod.

http://www.smithperformance.com/catalogue_fbstock.html

Anyone know if the bore size must change going from power to manual? Whichever I have now is fine (have to check the size). Might save having to buy a mc and not use it.

Edit actually I hate my clip on mc cover so I want to change anyways...

Re: 89 Formula: How to go to manual brakes?
 

Power assist MC will have larger bore because the power assist raises the pressure.

Some guys try to reuse the power assist MC when converting to manual brakes, typically these are the same guys that also re-use the power steering gear box when converting to manual steering.

Then they wonder why the car brakes and steers like crap.

Re: 89 Formula: How to go to manual brakes?
 

This will help:
http://www.tceperformanceproducts.com/dual-bias-calc/

Re: 89 Formula: How to go to manual brakes?
 

When I done my swap, I used the Strange B3360 1.0313" bore master cylinder. It came with a pushrod, rubber cover, and reinforcing plates. http://www.strangeengineering.net/hi...0313-bore.html

I bought a 3/8" IIRC rod end from summit to put on the pushrod and through bolted it to my pedal arm after drilling a new hole higher up.

I bought my brake line adapters and fittings from the www.chassisshop.com

As far as the fittings. Here's what I ordered
1) #889-f 1/8" NPT female to 3/8"-24 Tee
1) #891 3/8"-24 female to 1/8" NPT male straight
2) #892 3/8"-24 to 1/8" NPT male 90*
2) #896 10mm x 1.0 bubble female to 1/8" NPT male
1) #884 10mm x 1.0 bubble female to 1/8" NPT male 90*

Those parts was $42, shipping was $11.60, and that was Oct. 2009

Those was also fitting to install a line lock as well.

Re: 89 Formula: How to go to manual brakes?
 

I use a master cylinder from an 80's S10 that had manual brakes. Not sure what size the bore is but it has no problems providing pressure to the 4 calipers. I can slow down from 150 mph without needing the chute especially when there's a long shutdown area. I've applied lots of brake pressure to take the first turnoff from the track but the front brakes get a little too hot so I just run it down to the end. Front brakes are aftermarket race brakes with unvented rotors. Not designed for street use. My rear disk brakes are converted from 99 Jimmy rear brakes. See my thread in the brake section stickies about installing disk brakes on any differential.

Other than for drag racing, you'll probably want to keep the power brakes. You'll get much better braking force.

Re: 89 Formula: How to go to manual brakes?
 

Thanks for the comments guys.

I disassembled my mc and have (31.75mm) 1.25" front bore and 24mm rear bore. It was not obvious to me the front of the piston relative to front of car aka *rear* bore @ 24mm pushes the *rear* brakes and the back (again relative to back of car) larger part of the piston pushes the front brakes. That of course corresponds to where the brake lines go. Anywho makes sense now that i see it.

So at this moment I am leaning towards the Jegs setup from the link above. It has a slightly smaller front bore diameter (.125" aka 1/8" smaller) than my stock mc. Should suit my dual front LS1 calipers. Also comes with adapter plate, swivel and hardware. I will need to redo the mc to prop valve lines. I'm not clear if it comes with a pushrod. Online instructions talk about the pushrod not sure if they mean stock one or they include one.

Any more comments welcome. Again thanks for the guidance guys TGO rocks!

Re: 89 Formula: How to go to manual brakes?
 

the jegs kit is complete that is the one I bought !

Re: 89 Formula: How to go to manual brakes?
 

88 I was having a side conversation with RBob who went manual. He thinks a 7/8" bore is needed for going manual, that a 1" or higher and I will not be stopping the car.

I got the brake pedal and vac cannister out. Whats a good drill bit made of to get through that brake arm?

Re: 89 Formula: How to go to manual brakes?
 

let me know how it goes with whatever u get ,im contemplating selling the billet wheel s475 and picking up a second t76 and im going to have to do the same thing for downpipe clearance with my new up and forward turbo headers

Re: 89 Formula: How to go to manual brakes?
 

My strange 1.0313" bore MC works great. The car was a DAILY DRIVER for a few years with it.. In fact I went to the manual brakes due to it being a daily driver. My big cammed engine only makes 3-4" vac at idle. I had a vac can but my power brakes was not working. The can helped but only gave me 1 good push of the pedal... So I looked at my option.. Hydroboost system, vac pump, or manual.. I went manual.

My car stops as good as it ever has (even before the big cam), it does take a little more pedal pressure but I have no trouble even in a daily driver, stop and go condition. Also stops real well at the track. Was not prob slowing it down from 118 mph trap speed.

I used a good high speed steel drill bit in a 1/2" drill to drill the hole in my pedal arm


https://cimg3.ibsrv.net/gimg/www.thi...1d378f27ab.jpg




https://cimg4.ibsrv.net/gimg/www.thi...ec01ccede3.jpg


https://cimg5.ibsrv.net/gimg/www.thi...e205ed90ff.jpg


https://cimg6.ibsrv.net/gimg/www.thi...1dbc23ca47.jpg


https://cimg7.ibsrv.net/gimg/www.thi...be3c03d114.jpg

Re: 89 Formula: How to go to manual brakes?
 

Thanks Night. I think with my LS1 dual calipers up front I'm going to follow 88's path with the Jegs kit. I'm focused on the cold side turbo setup at the moment, I will post back when I get to the brake setup.

Re: 89 Formula: How to go to manual brakes?
 

I used a Mopar style MC, came from Dorman. I believe I bought it new on ebay for about $30, it's for an 85 Chrysler full size. it's 1.032 and probaly the same MC Strange sells you. I made a steel plate for the firewall and moved the pedal rod up. What i also did was removed my pedal quadrant and mocked it up on the bench. I then welded a piece of flat stock with a hole in it as a rod guide so there is no possible way on earth my rod can be pulled out and fall down. I also made a positive pedal stop to limit upward movement in case your foot caught under the pedal and you pulled up on it. All safety measures you might never need. The one thing I still want to do is make a brace from the strut tower to the MC. If you have someone pump the pedal you will see how flimsy the firewall is and there is quite a bit of flex. If you look at most NHRA 3rd gen stockers you'll see most have a brace.

Re: 89 Formula: How to go to manual brakes?
 

thats the MC i was thinking about , nice simple cheap setup

Re: 89 Formula: How to go to manual brakes?
 

Thanks for the ideas Beeman sounds like the way to go.

Re: 89 Formula: How to go to manual brakes?
 

Ed Quay supposedly has a nice setup as well. You send them your pedal and they do the conversion to make sure its in the right spot. I will be doing that this coming winter. Also Burkhardt Chassis as a kit.

Re: 89 Formula: How to go to manual brakes?
 

The Ed Quay site is not built yet but Great lead on the BC offering! The brace looks good too thanks!

Re: 89 Formula: How to go to manual brakes?
 

How much are you guys moving your pivot point up on the brake lever?

Re: 89 Formula: How to go to manual brakes?
 

Old thread but I thought I had posted what I ended up doing.

https://www.burkhartchassis.com/prod...aster-cylinder

Re: 89 Formula: How to go to manual brakes?
 

For you guys that used the strange kit (B3360), how did you use the 3 holed adapter plate as opposed to the 4 holed plates that come with the jegs and BMR kits?

And what did you use for the rod end?
The strange kit doesn't come with the rod end.

Re: 89 Formula: How to go to manual brakes?
 

I used the kit from malibudave here on the forums, it fit like a charm. I just bought his partial kit and used a 1 1/8th bore master for my four wheel four piston setup. Good setup and not costly.

Re: 89 Formula: How to go to manual brakes?
 

Hello,

Give me a call if you have questions about a third gen f-body manual brake conversion.

PH: 832-264-5566

We can walk through your setup and size the master cylinder to your front and rear brakes.

Re: 89 Formula: How to go to manual brakes?
 

Reviving an old thread, just wanted to mention that I had an unresolved issue of not being able to lock up the rear aluminum caliper PBR disc brakes even with the Wilwood prop valve all the way open. I even switched the lines at the MC.

I thought I could not bleed the brakes properly. But I never had a spongy pedal. In fact it's a rock hard pedal. After a few times on the track decelerating from 100 as hard as possible without locking up the fronts I think the issue is that there is is just not enough pressure going to the rears to cause them to lock up.

The rears do work (the pistons come out) and the e-brake has about 8 clicks to it, but I'm calling it a MC issue.

FWIW.

Re: 89 Formula: How to go to manual brakes?
 

Re: 89 Formula: How to go to manual brakes?
 

Burkhart takes the Strange mc and adds some stuff to make the manual mc package complete.

Strange says the mc is 1.032.

https://www.strangeengineering.net/p...313-bore.html/

I would like to adjust the rear pressure and get some more grip back there.

Do you have any suggestions?

Thx!

edit: hmmm I'm not sure how I missed your site back when I was researching....

Re: 89 Formula: How to go to manual brakes?
 

Usually, I would recommend a 7/8” bore master cylinder with your LS1 Front and stock rears.

You will have a longer pedal stroke going with a smaller bore master cylinder, but you will get increased line pressures, better pedal modulation, and increased clamping forces at the calipers.

With larger bore master cylinder and the 48mm diameter rear piston calipers, you may never be able to lock up your rear tires because those calipers may not generate the clamping forces needed to lock up a sticky tires.

You most likely will still run your adjustable valve wide open, but at least you should be able to modulate your brakes.

Re: 89 Formula: How to go to manual brakes?
 

Thanks for the info. The comments from others and Burkhart took me to the larger one. Perhaps someday I will revisit and try a smaller one.