Front disc brake conversion (Scarebird)

In one of the posts somebody says that we can use the 1989 Mitsubishy Galant 14" front disks for the Buick. will it match my 15" wheels ?

The Galant ( rotors ) disks are 11" in diameter, they are the specified rotor for the scarebird conversion.  You shouldn't have any issues with a 15" wheel.

thanks Regal, and will the main brake pump will match the space?

By brake pump do you mean master cylinder ( attached to firewall ) or caliper ( attached to scarebird bracket )? I'm going to presume you mean MC.

The OEM master cylinder will not be enough for the disc conversion -- you will need to replace it with a dual master -- seems the jury is still out on which one is the best fit both in form and function.

I've tried three different ones and finally settled in on a Wilwood 260-8555 for no other reason other than I think it's the best of both worlds but beware you do have to make some modifications for it to fit. I think this is the case for all the MCs though -- none are going to "fit" without some massaging.

I'm getting ready to plumb the new lines here soon and will add pics as I progress.

Hi Regal. what I meant is if I can use as well the mc from the Mit.Galant to install in my car?

No. The Mitsu MC to my knowledge will not work -- the scarebird instructions listed a MC or two they suggest. I wasn't happy with the fitment and as seen on this thread the consensus is still out on which one is the best -- it's far from a perfect conversion, as others have mentioned it requires a fair bit of forward thinking to complete.

If you re-read the thread you will see that there are at least three OEM style MCs used by three different people. I think so far the ones used by other members here are as follows:

1960 AMC Rambler
1980 Ford Fairmont
01-05 Chevy S10

txs so much sir.

I used an 80's Ford Fairmont manual master cylinder with a 7/8" bore. Minimal trimming of the frame required for fitment, Scarebird specs it to use, but it does seem to have a "long" pedal. (Very few miles on the brakes at this point) In other words it takes a considerable amount of pedal travel before the brakes firm up. So maybe a bigger bore would bring the pedal up. Manual brakes typically use a smaller bore MC than power brakes.

Interested to know how the Fairmont MC is working out for Keithg, see his earlier posts.

Regal, how did the Willwood fit and be interested in performance when done-1" bore or?

See earlier pages for pics of various MCs used. You should use a Disc/Drum MC of some kind. Baer Racing makes a very short MC, the Remaster, that comes in 15/16" or 1" bore and would fit really nice BUT it's like a lot of money.

62cutlassconvert wrote:Regal, how did the Willwood fit and be interested in performance when done-1" bore or?

I'll try to remember to get some pix of the wilwood unit in place.  I had to do some trimming of the seam along the bottom and of the cross brace to get it to fit.  Wasn't a huge deal but wish there was a drop-in.  The ReMaster is definitely a nice unit but based on the size shown on the spec sheet it might too still require some cutting.  Hard to tell till you have it in hand.

I bought the 1" bore unit -- supposed to be good for both power and manual brakes -- a member from the yahoo group indicated he went from the AMC MC to this unit and it improved the pedal feel tremendously -- figured I only want to mess with this once so I bucked up and spent the money after trying two separate OEM style MCs.

Well, I am still driving my CPP front calipers with the fairmont master. The pedal is too long for my tastes as well. I would recommend the AMC as it is 1" and would give a stiffer pedal. I do not know how it would be with the stock GM calipers as they are smaller bore than my CPPs, but my gut feel is that the fairmont would be too long for those as well.

I have been looking for a 1-1/32 master. I ended up buying one for a Ford pickup but have not put it in. I have a feeling it is too long, but have not trial fitted it. It is not yet on my short list, yet as the brakes work and are light years better than stock even with a long pedal.

Keith

Yeah, I'm running the stock S10 calipers and seem to have the same issue. Looked on Dorman and it does show a front disc applicaton for a 1976 CJ7 for that AMC MC. Might well be the option.

How is the bolt up pattern on the firewall?

Before I go through the considerable effort to replace the Fairmont MC I'll drive the car awhile. Just don't like such a long pedal.

I am not sure about the AMC master cylinder bolt centers. I had to widen the fairmont bolt center a bit to fit the Buick. Is it 3.125 or It is 3.375 on the Buick, I cannot remember. The AMC may be Is also not the correct width as it dates back to the 60s before the auto makers started the metric conversion.

I worried a bit about the disc/drum versus drum/drum when selecting a master cylinder, but as far as I can tell, there is no difference in the master and all I worried about is 1) does it have a 'deep piston' (only necessary if you are running manual brakes) 2) which side are the ports on and 3) what is the diameter 4) Does it hit the fender. The only other difference that there could be is the presence of residual pressure valves built into the master. I have read that some masters are supposed to have residual valves on the drum side of the master. Neither of mine have that and none of the ones I looked at had them either.

The Ford 1 - 1/32" does, but it is an extra part and I had to buy a Ford branded one one for about the same price as the whole master to just to get the residual pressure valve. All that and I probably will not be able to use it. Plus, Ford does not even call it a residual pressure valve. They call it a Proportioning Valve! how is it supposed to proportion anything if it is inline with only one of the pressure lines? This is the master I got: Dorman M39634 I do *NOT YET* know how well it will fit.

Keith

Here are the promised pix...took them with my phone so the quality isn't the greatest.

As a side note the bolt center spacing for the MC on our cars is 3.40"  The Wilwood unit has slotted openings.  

As you can see I had to cut a fair portion back.  Right now I'm just roughing everything in so I'll take it all back out - massage it a lil more and throw some touchup paint on it for looks. I'll try to remember to take a pic when it's back out so everyone can see to what the extents of removal were for me.

I included some pix of the prop valve and pushrod I'll be using and some pics showing the disc conversion / suspension install.  Yes, I know I have a handful of cotter pins that need to be bent up but I didn't want to till I knew it was in for the final time.  I'll do that when I go to grease everything.

Guys.... Does anyone know why kind of studs I should get if im trying to convert my front to 5 lug at the same time? I've got some 65-69 corvair hubs. I ordered a couple of boxes of Dorman 610-114 like suggested here but then forgot you were keeping the 4 bolt pattern.

The bolt pattern won't matter. You need to confirm the knurl on the studs you have will provide an interference fit with the corvair hubs, if not you'll have to find a size that is either larger or smaller accordingly.

In my case I ended up using metric studs on my conversion because they kept the head of the knurl short and I was able to find one in an appropriate length and knurl diameter. Just to be safe though I tack welded each one in on the backside of the hub.

I don't recall the part # I ended up with but I do know the total length was about 1.9" long and it was an M12 X 1.50 thread. I think the knurl was around .542

According to Dormans site a Corvair stock stud is 7/16" X 1.5" long w/ a knurl of .472. You are going to want an approx. 2" long stud. You can stick with the 7/16" if you want or you can change -- that is up to you. Your knurl on the new stud needs to be about .48 or so and IIRC have a shoulder height of approx a 1/4".

Hope that helps.

Google wheel stud chart and you should be able to find a listing that shows all the studs available, they're part #s, and all the pertinent info so you can find one that looks like it will suit your needs.

GL!

Ive been a little slow with the updates lately. The brakes took me awhile to get sorted out where I'm happy with them. Here are some pics of the MC fully installed.

Pedal is great, couldn't ask for much better with manual brakes if you ask me.

Part of what took so long was waiting on the SS lines to be made up -- I bent romex wire to shape and then sent it off to have the pcs formed for me by Inline Tube -- they did great.

Additionally, I've wired and confirmed the brake lights work well with the switch provided and installed on the proportioning valve.

Next up - finish bending cotter pins and greasing the new front end. Touch up some paint around the ball joints that was marred during installation. Cut the rear springs ( gonna start with 3/4 coil to see how it sits ). Then I should be ready to take it in for an alignment.

Looks nice! When I get around to brakes again, I'll probably try a 1". I did some more looking and am pretty sure the 1-1/32 master I have will not fit. I'll just ebay it.

As for the brake lights working, mine did as well. It is just that when coasting to a stop sign with enough pedal to slow the car, but not a hard stop, my switch would not turn on the lights. I had a couple people tell me that my brake lights did not work and I checked and they did work. This is why I wired up a pedal switch. I feel much better with that as it turns the lights on when I move the pedal, not after sufficient pressure in the hydraulic system is available to flip the pressure switch. The Wilwood switch may be a lower pressure threshold, but I do not know. The pressure switch activated brake lights appears to be a common problem for hot rodders, too, and they suggest a Harley Davidson switch with a lower pressure threshold or a pedal switch. The HD switches are pretty expensive and I wanted to give the people behind me a bit more warning about my intentions, anyway.

YMMV,

Keith

I agree on the switch part Keith -- I haven't had it out of the garage to test yet -- wife pushed the pedal though for me and it appeared from what I could tell that it came on almost the moment she pushed the pedal. I know you mentioned you had a really long pedal -- with the Wilwood MC the pressure on the pedal is almost instantly there, maybe that has something to do with it?

I will definitely report back once it's back OTR. If needed I'll had a pedal switch too just like you did -- don't need anyone riding in the back seat less I let them lol

Appreciate the kudos BTW.

Getting ready to do this same conversion to my 1963 Special. I haven't been able to locate the tech bulletin on removing the old studs out of the drums. Looks like from what I've read here that it's just drilling the back out with a 9/16' bit is that correct?

Also, what studs is everyone finding is best? The only ones in the thread are the dorman 7/16-20 Serrated Wheel Stud at 1 21/32, are those plenty long enough?

There are really two ways to remove the wheel studs.

1.  Drill out the backside and pop them out the front.

OR

2.  Take a die grinder or similar and grind the swaged ( splg?? ) area at the base of the stud ( wheel side of stud ) and then  take a deadblow or similar and knock them out the back.

#2 is how I removed mine with no issues.

As for the replacement studs, see my post about 5 posts up from here -- I ended up using metric studs on my disc convo -- really a bunch of different options out there, just make sure the length bought is around 2" long.  I tack welded mine in for piece of mind.

Thanks Regal, was able to get them out. I'm noticing that the hub doesn't seem to pull in as far as I would expect into the disc. I thought I saw somewhere that the hub diameter needs to be turned down but can't seem to find it. Do you recall how much you took off (or did you)? From the pics I can see that your hub is settled much further into the disc than mine, so I'm curious if there was a modification there.

Yes - I had to take material off the circumference of the hub, IIRC it ended up about an 1/8" all around or a total of 1/4" less in diamater if that makes sense?  Just measure the inside of the rotors you're using and then turn the perimeter down to get it as close as possible.  Less side to side slop the better.

The hub should mate flush with the backside of the rotor hat.  I had to have my hub faced for flatness as well in order to achieve this.  Not sure how buy my hubs when placed in a lathe had some wobble -- facing them fixed this -- that really solves two problems.

1.  They sit better against the rotor hat.
2.  You shouldn't experience that wobble going down the road.

We can thank Keith for this tidbit as he experienced it 1st and mentioned earlier in this thread.

Other things I ought to mention.  If you intend to install aftermarket rims at some point I would go ahead and turn down the outside diameter of the bearing/spindle bore on the rotor side some, right at the base of it.  I think I took off about an 1/8" all around here too and went up it about 3/8" -- on my present wheels the center cap wouldn't fit on because it was smaller than this.

This was brought to my attention from another member here as well.  Sadly he sold his car but I think he still lurks around occasionally so if you're reading this tx Tim!

Additionally I replaced my soft brake lines from the caliper over to a braided Fragola hose.  I told the counter person I wanted 14".  Well I think they're really 2" too long.  I know where the problem lies though and I can only blame myself.  He gave me a 14" hose but when you assemble the fittings with too it added atleast 2" to the overall length.  They work but I intend to change them at some point.  I'd really like them to be 12" from end to end with fittings assembled to hose.

Be sure when you do finally bleed the system that the bleeder screw on your new calipers is facing upwards otherwise you'll have an air pocket you'll seem to fight forever.  I'm not certain all the calipers listed in the conversion are identical but the ones I ended up with I had to leave the passenger side off the rotor with a spacer in between the pads so I could bleed it properly -- just fyi.

Feel free to ask any questions you have -- I'll do my best to help steer you in the right direction.

Thanks, this is all great information. I had read earlier about the wheel wobble, so my plan was just to take my rotors and hubs down to a machine shop to have them turned and faced if they need that as well. I'm still waiting on my actual brackets to come in, so I can check clearance. When I bought the car originally it had 15' rims on it already, so those are what I have to work with. I didn't even think to check the spindle bore. Much appreciate the assist.... I'm sure it won't be my last question.

You bet!! Glad to help!

Rims... I'm about ready to move forward with my F85 disc conversion but I need to sort out the wheels. I'll be going to a 5 x 4 3/4 bolt pattern but want to keep the look stock. I have the dog dish caps that I want to keep but on a 15" steel rim. I can only find these that will use the 10 1/2". I have the smaller 9"(ish). Does anyone know where I can get 15" rims that will take my dog dish caps?

EDIT: ok, does anyone know of 14" steel rims that will clear the disc conversion?