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Ed,
Yes, my car has the 4 wheel discs and still has the stock master cylinder.
I also thought more about the caliper area difference between the single piston and LS1. The LS1 caliper piston area is only 6% more but the front brake section of the master cylinder supplies 2 calipers. So the master cylinder will have to supply 12% more fluid.
Or will it? The master cylinder has a separate brake line for each front caliper. Are there 2 pistons in line with each other in the master cylinder bore to supply the front brakes? If so, then each piston is back to a 6% increase in fluid volume. Hmm...
Slayer2000,
I have thought about the LS1 master cylinder also. I'm not sure about the threads on the brake line fittings or whether it would bolt up to our booster. I will be leaving my stock rear calipers/discs on for now. I wonder how the stock rear calipers would react to the LS1 master cylinder.
Does anyone know the diameter of the LS1 rear caliper pistons?
Originally posted by slayer2000 with regards to the master cylinder, couldn't you use one out of a 98 and up f body that had these brakes to begin with? I've got a 4 wheel disc setup on my car factory(90 gta). Will I need to look for a new master cylinder?
thats a good question..
doesnt the 4thgen master cyl just bolt up to the booster? im pretty sure they're the same bolt pattern atleast...
if it doesnt bolt to the 3rdgen booster, is there anyreason you couldnt run the whole 4thgen brake booster/mastercyl?
think about it... the pedals bolt up thru the boosters holes, and they're the same on 3rd and 4thgens........ should bolt in as long as it doesnt hit anything.
Thanks Chuck. IMO, I'd switch to the disc/drum (IE-1LE) master when I install these brakes with dual piston calipers. That's what the factory uses and so do I. Unless you guys are brake gurus and know much more than I do about what you're doing, in that case dismiss all I say...
And as far as I know from the illustration manual, there's only one piston in the master for each brake line, front and rear, but the front splits to each side. There's other guys that know the piston diameter of these things, I just do what the little book tells me. I know Alloy has done a LOT of research into this, maybe shoot him a line.
I would try it the breaks with the stock proportioning valve before you switch to the 1LE valve just to get a feel of the difference. It would seem that the 1LE proportioning valve is a better match for the LS1 brakes. What valve are the C5 guys using? The C5 caliper has very close if not the same hydraulics as the LS1 caliper.
My car already has 4 wheel discs but I thought the main difference would be the in the master cylinder. Wouldn't the prop valve for my car work better the a 1LE disc drum setup? I can get a 99 camaro master cylinder pretty cheap but I'd like to use my current one if I can. If it can't produce the correct amount of force on the new front discs what kind of problems am I looking at? eb, That setup you've got looks awesome! I hope mine turns out as well.
Eb, I was just wondering if you could use countersunk allen head bolts for the caliper bolts. If so you would have plenty of clearance. Also could you possibly post a pic of a modified spindle by itself with no hub or bracket? I want to make sure of my cuts before I screw them up.
Originally posted by slayer2000 Eb, I was just wondering if you could use countersunk allen head bolts for the caliper bolts. If so you would have plenty of clearance. Also could you possibly post a pic of a modified spindle by itself with no hub or bracket? I want to make sure of my cuts before I screw them up.
Allen head bolts would give good clearance you have to buy new bolts anyways because the stock LS1 bolts are way to long. As for the spindle pics, go to the second page of the C4 thread and I posted pics of the needed modifications to the spindle: http://www.thirdgen.org/techbb2/show...5&pagenumber=2
89 IROC Z,
My plan is to use my stock disc/disc master cylinder with the LS1 up front and the stock single piston calipers out back. I plan to test it out conservatively at low speed to find out how it works. I can always change the master cylinder if it doesn't work well.
I dumped the stock proportioning valve long ago in favor of a Wilwood adjustable unit. I would recommend this to anyone who doesn't mind bending/flaring some brake lines. The ability to tailor brake bias to what you want rather than what some GM designer decided worked well is the way to go.
Slayer2000,
If you cannot develop the proper force on the front discs you will probably have weak braking. The LS1 pistons have greater area than the stock calipers so all other things equal, you should develop more clamping force from the front calipers. This could affect brake bias (an adjustable proportioning valve would sure help this). My theory is that the greater LS1 piston area will give you a lower brake pedal than the stock calipers because more fluid is required to move the larger pistons. I'm not sure how much lower though. Of course us 4 wheel disc guys are used to a low pedal anyway because of those poorly designed rear calipers.
Maybe you guys already know this, but I thought I'd mention it for those who don't. If you are making your own caliper mount brackets, avoid creating sharp corners. This is important on the section of the bracket that curves around the 2 outermost bolt holes. Get out the file or grinder and round off these corners instead of leaving them at a right angle.
I learned about this earlier this year when I found the torque arm bracket on my 9" rear was cracked. I took it to be welded and 3 different guys at the machine shop all commented that it was poorly designed because of the right angle corners at 2 locations. Those right angle corners are exactly where the bracket cracked. By the way, this bracket is 1/2" thick steel.
OK guys, could someone explain the spindle mods one more time?
I checked out the pics on page 2 of the C4 thread as 89 IROC Z suggested but there are a lot of pics. I do not know for sure what ones to look at.
Do we cut off the steering stop or not?
I thought I saw a page with detailed spindle mod photos somewhere. It had photos with "cut here" lines drawn in and maybe tips for what not to do. Does anyone else remember seeing this?
I hope I'm not beating a dead horse here, but I am hoping to mod my existing spindles correctly without ruining them.
z28 doyle, Go back to the c4 link on this page and go to the 4th post down by alloy. There's a pretty good pic of the back of the spindle. the steering stop is on that spindle so I guess you should leave them alone. I am going to try to contour mine a bit closer and smoother so my caliper has plenty of room.
z28cdoyle,
Go to the c4 thread as I said above I posted pictures of the spindle modification. I didn’t post any other pics of the spindle modification in this thread so it should be straight forward.
OK guys, thanks for the advice. I see the pics you are talking about 89 IROC Z. I think tomorrow after work I will fire up the reciprocating saw and grinder and start cutting.
Mike,
I won't be running at Summit this weekend. I was at beaverun the last weekend in September and incinerated my brakes. Instead of replacing rotors and spending the entry fees for another track day I decided to put the money into the LS1 swap and call it a year. I'll be back next year with some real braking power for the front straight at Summit.
I "think" the stop CAN be left alone, or have minimal adjustments made to it, with the LS1 stuff, but on the C4 system it must be removed. I just haven't got another set of spindles to try it yet.
oops! I already cut mine off. what exactly will happen if anything without those stops? Also I was wondering instead of using 1/16 spacers if you could just make the bracket 7/16? I'm planning on using flathead cap screws and countersinking them so bolt clearance shouldn't be a problem. Am I missing anything here? I also got a 98 firebird master cylinder cheap so when it gets here I'll look at how it fits(line fittings and so forth) and I'll let everyone know what I find out. I'm going to try out my stock mc first just to see what happens but if anybody gets this done before the next 2 weeks or so I'd like to hear about it.
oops! I already cut mine off. what exactly will happen if anything without those stops?
It's been debated, but unless you turn hard left or right, and THEN hit a curb, nothing will happen. The lowest bolt head will take the place of the stop. Only a SEVERE hit will damage the bracket, but all you'd have to do would be to replace it and you'd be back on the road. I SERIOUSLY doubt much will hurt the 3/8" thick bracket...it's a bonzer!!
Quote:
Also I was wondering instead of using 1/16 spacers if you could just make the bracket 7/16?
Again, 7/16" is really overkill for bracket thickness and would be a bitch to cut and drill, unless you have it lazer cut then I guess it would work. My brackets will stay 3/8". Good idea on the countersinking idea. I thought of that but decided not to. I do want to refine the design to do away with the need to make clearance there though.
I have one side of my car almost finished. I am still using my mock up bracket made of plexiglass but it is working well enough to decide where holes need to be and where to grind for clearance. For anyone making their brackets, the plexiglass is nice to use to get a pattern to make your real bracket. Easy to cut/drill, and transparent to see where the holes have to go.
I used the bracket drawing posted by 89 IROC Z. I moved the holes for the caliper carrier a little. I spent a lot of time tweaking the position of the carrier so the brake pads were contacting the rotor face properly along with leaving as much clearance as I could get from everything else around the caliper.
Steering stop
I cut mine off. I tried to find a way to leave it on but I just do not think it will clear the lower caliper carrier bolt. Maybe if you use an Allen head bolt you could leave it and just grind for clearance.
You may not need it anyway. On my car the steering stop on the A arm still contacts the bottom arm of the spindle about 1/2' forward of the bracket bolt. The steering stop on the A arm seems to be mounted at an angle such that it was never really contacting the extension on the spindle that we cut off for this mod.
I think you could fab another stop easily enough to replace the one that was cut off.
Also I was wondering instead of using 1/16 spacers if you could just make the bracket 7/16?
Note how Baer also uses "spacer washers" on their 9 bolt brake system backing plates in the thread below. They weld the washers to the plates and then "cad" plate them for protection. These plates go for $150 if you buy them outright!!!
OK guys, I don't understand what went wrong. I finished my final bracket tonight out of 3/8" steel. It looks real nice but it won't work because it is too thick. When I bolt this up, the caliper carrier is touching the rotor even without the spacer washer Ed mentioned. WTF? The only option I can think of now is to start all over again with a 5/16 thick bracket and no spacer washers. This may center the carrier over the rotor. I may even have to go all the way down to a 1/4" bracket with spacers...boo!
Any ideas what happened?
Oh by the way, with my other development bracket I tried the setup in my 16" GTA wheels...bad news...the caliper rubbed the wheel. It was rubbing on the honeycomb part of the wheel not the weld bead. I think with new brake pads this may be a big problem since grinding the stiffening ribs on the caliper won't help here. Lots of clearance witht the 5 spoke IROC wheels though. Looks like the GTA wheels will have to go on Ebay.
At least you guys got that far. I can't find a piece of scrap steel to save my life! I did find the 12mm 1.75 flathead capscrews at a fastenal dealer. I have everything else ready to go except for that and some paint. This may take me a few weeks . z28cdoyle, I may have the same problem. My mockup bracket is 1/4 thick cardboard and 2 1/16 washers and it looked a little close. I hope I just made a mistake but if I can I'll see if I can find out something this week.
Chuck, I don't know what's wrong. The only thing I can think of is that you may need to clearance the spindle in the area where the bracket "meets" the spindle. Since I make my brackets by hand, they don't always come out perfect or exactly like the plexi template, no two the same. I have found that occasionally I need to grind a small amount of metal off either the spindle or the bracket in the areas around the upper and lower bolts that attach the bracket to the spindle. If you have a small amount of interference here, the bracket won't sit flat against the spindle and may cause the bracket to sit higher than it should. Otherwise, I don't know what the problem is. My carrier sits exactly even over the rotor. Here's a pic for reference (sorry, no Photoshopping done to it.) If you look in the area straight above the lower bolt, this is the lower area of concern.
Ed,
I also made my bracket by hand and added a little more "meat" around the bolt holes so I had to grind it in a few places for clearance. My bracket is sitting flat on the thread bosses on the spindle and is not touching anywhere else.
Did you mill the thread bosses on the spindle where the bracket bolts are? I could probably center the carrier on the rotor this way with the 3/8 bracket but I don't have anything to do this with. I would have to use my grinder and I do not think I could keep the mounting surface flat. I think I would rather make a 5/16 bracket. I'm not sure if this is a common thickness for steel but I will stop in a my local scrap yard tomorrow and find out. If not, I may take the spindle to the machine shop that turned down my rotors and ask if they can mill 1/16 off the thread bosses. Stay tuned.
Slayer2000,
Did you try calling machine shops, welding shops or recycling yards? They will probably have steel pieces laying around.
I haven't touched the threaded areas of the spindles with a grinder but I will comment on one thing:
As mentioned WAY back in the 1LE thread, there are 2 types of spindles, I call them the "early" and "late" designs. In the "early" design, the area around the threaded holes is totally flat. In the "late" design, there is a raised boss around the lower hole that needs to be tapped. I thought this would cause a difference in where the bracket sits (height wise) but it didn't for me. The brackets sit the same regardless of what type of spindle I put it on. I doubt this is the case but it may be your difference, but having tried it myself I don't think this is it.
Concerning the steel, I had a hard time locating 5/16" thick steel sheet which is why I went with 3/8"...it's popular. Luke said the original Baer bracket is 5/16" thick but I have no idea where to get it.
Although I don't need to, I have thought of putting a regular wheel spacer between the hub and rotor to move the rotor out...maybe this would work for you.
I think you are right about variations in the spindle causing the spacing issues Ed. I just took a close look at my spindles. I think I have one early and one late. I had to replace one a few years back when a wheel bearing to welded itself to the spindle. I must have gotten a late style replacement from the salvage yard. I really think the thread boss will make a difference. My caliper carrier is about 1/16" too close to the rotor which looks to be just about the height of the thread bosses on this spindle. I plan to cut my other spindle this weekend (no thread bosses) and try my 3/8 bracket on it. I'll let you guys know how it turns out.
I went to the scrap yard today and got some 5/16 steel. I will probably make you guys jealous but this place has a pile of steel about 6 ft high. I found everything from 1/8" to 1/2" thick pieces.
By the way, good idea on the wheel spacer under the rotor. I have some but I think I will correct the spacing with the bracket thickness.
You know, come to think of it, I only fit up the C4 kit on both styles of spindles, NOT the LS1s. I fit up the LS1s on the "early" spindle, that has the flat area. This may just do it for you.
I finally gave and milled down some one inch thick cold rolled I had laying around. A cincinnati mill and a 4" carbide insert shell cutter made pretty quick work of it. I went ahead and took them down 3/8 thick but I will have to wait to drill them and cut them to shape. I noticed the bolt holes on my spindle are a little lower because the flats they're drilled into are machined a little deep in the casting. I'm going to grind my spindles smooth in that area as well as knock off the casting flash on the rest of it. I hope I have something else to report monday.
I got my brackets done last night and heres what I found. I had to grind a little of the spindle casting away to get it to set flat and line up the bolt holes but nothing major. Also even without the spacers my carrier doesn't sit centered over the rotor. It's not touching but it's not right either. I'm going to put the carrier in the mill and mill off .025-.035 from the bosses. I think that should fix it. The flathead capscrews worked great so there's plenty of clearence there but I still need to grind a little off the spindle to clear the caliper. I let you guys know more tuesday night.
Last edited by slayer2000; 11-10-2003 at 12:46 PM.
OK guys, after 13 hours in the garage Saturday I'm finished with the brackets and spindle mods. Man that steel is hard on sawzall blades. I wanted as much "meat" on the brackets and lower spindle bolt area as I could get. I took 89IROC-Z's bracket design and made it bigger around the bolt holes where I could. I ground the spindle and brackets for clearance around the caliper pistons a little at a time until they fit but without taking off too much metal. All I have to do is paint the parts, get some grade 8 hardware and put it all together.
By the way, the early and late spindles make no difference in the required bracket thickness. I made mine out of 5/16 steel for both the early and late style spindles. The carrier is centered over the rotor without any spacer washers. The reason one bracket thickness works is the thickness of the spindle "arms". One style (I'm not sure early or late) has the raised thread boss and one doesn't. The spindle without the raised thread boss is thicker by about 1/16" (about the height of the the thread boss). So GM eliminated the thread boss and made the whole spindle thicker to compensate. I had to grind my spindle (the one without the thread boss) to get my brackets to sit flat just like like slayer2000 mentioned. I didn't have to do any grinding on the other spindle.
I still can't explain why the 3/8" bracket worked well for Ed but the 5/16" worked so well for me.
I brushed over this entire thread for a possible answer (Maybe I missed it in there somewhere) But anyways-
What do the 4th gens use in the way of hubs for the LS1 brakes you are retrofitting? It must be obvious they don't interchange onto the spindle otherwise you would be using them? Is this correct? or is it just an offset problem?
Originally posted by z28cdoyle Where can I find class 10.9 bolts for the caliper carrier? All I can find are class 8.8 bolts.
I am looking for a set of bolts too. Does anyone know where you can buy Allen head bolts?
Quote:
Originally posted by AGood2.8 What do the 4th gens use in the way of hubs for the LS1 brakes you are retrofitting? It must be obvious they don't interchange onto the spindle otherwise you would be using them? Is this correct? or is it just an offset problem?
The hubs on 4’th gens are sealed and bolt to the spindle so there is no chance of using them.
You could try your local napa for allen head bolts. I had a hard time finding the cap screws I used and I ended up going to fastenal. I'm sure they are on the web. I know you could get allen bolts from them. You might also try j and l, grainger, or mcmaster carr. I'm trying to post my pics but I don't have my camera's software disc. I'm going to try to find it and post this weekend.
Hey guys there is a guy on the montecarloss.com boards that has found a way to use the 13" c-5 rotors and get by with a smaller rim but unfortunately ,or fortunately depending on how you look at it, you have to use wilwood 4 piston jobs. They are only 100 bucks a pop and well worth it. Just pointing out some other options. By the way the monte spindles are almost identical to the 3rd gen spindles brake wise. You might also want to look into the tall lower ball joint thread, this could help to get some camber gain in the 3rd gen strut setup. I can explain how it works if the thread is a little long for ya.
I just checked out the c5 monte brake thread. That setup looks awesome I'm still trying to get my camera to make nice with windows xp so I can get my pics up. I'm off for the week after thanksgiving so I'm going to get to work then. I'm going to do the heads, intake ,cam headers and convertor first then do the brakes. By the way anyone know what they are going to do for a proportioning valve? I have a 99 ss master cylinder but should I use it's prop valve too? Also I've decided that I'm going to mill down the carrier thread bosses .062 to center my calipers. I really don't want to make new brackets and I can't mill them because of their irregular shape so this seems to be the best solution.
I found a local fastener store that sells class 10.9 bolts. I picked up 4 for $1.70 which should be all I need to put the whole setup together. Man this metric hardware is hard to find. I tapped my spindles with standard threads and used easy to find grade 8 bolts for the brackets.
Unfortunately, I will probably throttle back on this project for a while though. I have some other projects to do on the car that make sense to complete while I have the front end and brake system apart. With all this other work, I will probably not finish until after the holiday season is over.
I will try to get some pictures posted early next week.
By the way, if anyone is looking for extra length wheel studs, NAPA 6411581 cross reference to Dorman 610-323. These are the same diameter and thread pitch as stock only longer. They cost me $18 for 10. NAPA also has copper washers for the banjo fittings on the brake hose for about 50 cents each. Advance wanted $2 each for them.
Slayer2000,
You should consider installing an adjustable proportioning valve and forget about the stock unit. I put a Wilwood adjustable valve on my car and gutted the stock valve a few years ago. Wow, what a difference. They don't cost that much and are not difficult to plumb into the system. With all the modifications and adjustable aftermarket stuff we put on our cars it's a little suprising more guys don't run adjustable proportioning valves.
I'm a little leary of them because I don't have a lot of experiance with brake systems. I may well have to get one and learn them pretty quick though. I'm still going to try my factory setup first and see how it goes. I hope it will work but if not I'll go with the newer mc.
Okay, I milled my carrier bosses like I said but I only needed .040 to center the rotor pretty well. I accidently took .058 off of one so I'm going to make a couple of .018 washers to fix it. If I hadn't had my head up my butt I would have been okay but oh well. Still can't get pics yet but I'm still trying.
what exactly will happen if anything without those stops? Also I was wondering instead of using 1/16 spacers if you could just make the bracket 7/16? I'm planning on using flathead cap screws and countersinking them so bolt clearance shouldn't be a problem. Am I missing anything here? I also got a 98 firebird master cylinder cheap so when it gets here I'll look at how it fits(line fittings and so forth) and I'll let everyone know what I find out. I'm going to try out my stock mc first just to see what happens but if anybody gets this done before the next 2 weeks or so I'd like to hear about it. 
. z28cdoyle, I may have the same problem. My mockup bracket is 1/4 thick cardboard and 2 1/16 washers and it looked a little close. I hope I just made a mistake but if I can I'll see if I can find out something this week. 
I'm still trying to get my camera to make nice with windows xp so I can get my pics up. I'm off for the week after thanksgiving so I'm going to get to work then. I'm going to do the heads, intake ,cam headers and convertor first then do the brakes. By the way anyone know what they are going to do for a proportioning valve? I have a 99 ss master cylinder but should I use it's prop valve too? Also I've decided that I'm going to mill down the carrier thread bosses .062 to center my calipers. I really don't want to make new brackets and I can't mill them because of their irregular shape so this seems to be the best solution. 
If I hadn't had my head up my butt I would have been okay but oh well. Still can't get pics yet but I'm still trying. 
