89 Iroc Z

alacran & others,
There is a slight issue with the LS1 bracket that comes more apparent when I used the design on the CTS-V bracket which has the same mounting position. It still works but is not perfect. The top mounting whole is in fact a little off.

I have since redesigned the bracket but have not had it cut out at my local water jet place to test. I can give you guys the bracket file if you want to try it out. What I did this time is found the center point of the spindle, then measured out in a circle to calculate the point for the two mounting holes.

Edit: The new file is up on my site: http://lukeskaff.com/?page_id=355

88gunmetalgta

iTrader: (1)

Have you incorporated a little more clearance into the area where it passes closest to the pistons? I found 0.05" was sufficient.

alacran

never mind.

alacran

We got to work on this last night and here are the pictures of the top spindle bolt off location.

First, here is the bracket we are using (AKA CTS bracket), i layed it over the drawing...

one more but this time the CTS bracket is layed over the LS1 drawing (link only)
http://i144.photobucket.com/albums/r...p/IMG_1113.jpg

Now here is the problem we are seeing...


Basically, the top of the abutment bracket (left in the picture) is higher than it should be and causing the bottom (right hand side) to touch the rotor.

we proceeded to mount the wheel and we had a rub between the wheel flange and the abutment bracket...


After several iterations of mounting schemes trying to resolve the issue without cutting the bracket or the wheel. I decided to take the top spindle bolt out but leave the bottom spindle bolt on and lightly torqued.

This allowed us to move the spindle bracket with the abutment bracket attached. Essentially moving both brackets together. This produced promising results. Now the abutment bracket lines up well and the rub is gone.


another shot...


more pics (link only)
http://i144.photobucket.com/albums/r...p/IMG_1092.jpg
http://i144.photobucket.com/albums/r...p/IMG_1093.jpg
http://i144.photobucket.com/albums/r...p/IMG_1095.jpg

In conclusion, the best way to fix the alignment issue is to relocate the top spindle bolt and release another bracket design. We ended up slotting the bolt hole in the bracket. I am trying to modify the drawing for the new hole location but it is going to take some time to complete it has been a while since drafting class.

pictures of modified bracket...(does not look safe but plans are in works to ensure the bracket will not move)
NOTE HOW MUCH THE CALIPER BOLT HOLES MOVED AFTER THE MODIFYING THE TOP SPINDLE BOLT HOLE (NOT EQUAL)



Let me know if you have any questions.

Also, as a point of clarification this does NOT fix the caliper/spindle clearance.

Nick

89 Iroc Z

Here is my new bracket design.. Please give me feedback on how it fits, I have not had it cut out yet so I am not sure if it is perfect yet
http://lukeskaff.com/DropBox/LS1_CTS-V_bracket_Beta.zip

Both caliper mounting holes are moved in this new design, it should center the caliper on the router better. There may be a slight clearance issue with the lower spindle bolt part of the bracket hitting the caliper bore, let me know.

Here is a picture of the difference between the two brackets, the cyan is the new and the red is the old.

89 Iroc Z

Here is another picture demonstrating the problem. The old bracket center point did not match the center point of the spindle. I had to try and measure out the center point of the spindle from the spindle mounting bracket holes. Makes me with I had access to a Fargo Arm. Now that the center point is more in-line with the center point of the spindle I may have to tweak the radius of the spindle mounting holes to have the brake pad located on the router properly... It may be too close or too far away from the the center-point.

alacran

At this point all i can offer is verification that the bracket design works as we have at least one spindle modified and will be modifying the second shortly.

We need some help getting the brackets cut out. I am looking for a new source.

TIA
Nick

P.S. Luke looks like the the top spindle hole moved up by 0.090" in y-direction and 0.180" to the left in x-direction (towards the caliper bolt hole). I would greatly appreciate a cad model of this change, incorporating the necessary changes to the outside of the bracket.

This way i can try both brackets and provide feedback as soon as i can locate a source to cut them

alacran

i found a source to water jet the brackets for me. Now i need to make templates and determine what route i need to take. Stay tuned.

FirehawkSS

iTrader: (2)

Thanks for taking charge on this issue. Looking to do this upgrade as soon as I can source parts. One question I would like to ask is if anyone has a dimension from the center of the hub(axis of rotation) to the furthest point outwards on the caliper. Basically I'm looking for a radius from hub to caliper. I want to double this measurement and check if my wheels will work.

alacran

Sneak peak...

alacran

Beta is more better...

Luke, the new design fixed the alignment issue and did almost exactly what my modification did. We still need to do a wheel mock up but i figured i would post images of the progress so far.

@firehawk - looks like the center to the top of the LS1 caliper is between 7" and 7.5" (With the beta bracket the top of the caliper is the highest point.)


Now pictures of the mock up...
(Back)


Front


bracket to rotor
(bottom)


(Top)


caliper to spindle


Any questions? Stay tuned for the wheel mock up...

89 Iroc Z

alacran,
Thanks for trying it out and the update! I am about to get the beta bracket laser cut but had and idea after looking you pictures. For the LS1 brakes it may be better to rotate the caliper on the center-line of the spindle so the space between the two caliper bores is where the caliper sits over the bottom spindle mounting hole. There seems to be tight clearance between the bottom caliper bore and spindle, rotating it would fix this. If you give me some measurements I can get two brackets cut, the beta and a rotated caliper bracket.

If you take a zoomed out view of the back of the spindle with the caliper and bracket mounted I can draw on the picture and show what measurements I am interested in.

88gunmetalgta

iTrader: (1)

Looks like you'll run into trouble rotating the caliper up. His spindle isn't clearanced enough for either abutment bracket bolt. And the steering stop would definitely have to come off. What about rotating it down a few degrees?

alacran

if rotates up the lower caliper bolt would have to leap frog over the lower spindle bolt and that would cause the top to crash into the strut support.

Also, i would not rotate it down any further. aside from looking weird i can only image what debris would start to fall into it. I want to keep the caliper towards the top half of the rotor.

I will post better picture of the back.

On page 6 Jerrywho did this...




not sure if it worked with a stock strut but it may be worth a shot.

I also have c6 calipers to mock up with.

Wait, Luke you need to update your original post. The bores of C5 and C6 are smaller than LS1. I am thinking the C6 may have more clearance.

Nick

88gunmetalgta

iTrader: (1)

We're only talking a move of around 5 degrees, either up or down. Just enough so the bolt doesn't line up exactly with the piston. From your pics tho, it still looks like you would run into trouble rotating it up even a little bit.

alacran

Of course, i get it now.

89 Iroc Z

This is what I am thinking in terms of moving the caliper, just a few degrees

89 Iroc Z

MY LS1 calipers are in storage, I will have to go get them after I get a bracket made. What is the distance from centerline to centerline of the LS1 caliper bores? I need to know this to know how much to rotate the caliper.

89 Iroc Z

Here is what the bracket looks like with the caliper moved down, sure looks goofy. I can't say I like having the caliper that low either. It is probably best to leave it as is and clearance the spindle to clear the bore. There is still enough material on the spindle for my comfort. The loading is also not in the direction of the thinnest part of the spindle so I do not see any issue there.

89 Iroc Z

I reshaped the beta bracket a bit to make sure it clears the CTS-V brembo caliper casting. I also tried to smooth out the lines a bit from alacran's feedback.

FirehawkSS

iTrader: (2)

Thanks for the pics and the measurements! After looking at the pics that alacran posted I am a little bit concerned. It seems like there is hardly any spindle left to bolt to after all the cutting and shaping. Im specifically talking about the caliper to spindle pic. Is this the same area that 89 Iroc Z is talking about? Looks like less than 1/4" in the pics.

89 Iroc Z

FirehawkSS,

I would not be to worried about that, the load applied the the mounting hole is not in the direction of the spindle clearancing.

alacran

Here is the image of the back of the spindle, with everything assembled.

kickass92z

I just want to say this, you guys are freakin awesome! I am looking for info on a rear swap, sorry for the thread jack. I bought a wrecked 2000Z, and am about to start pulling parts. I bought my car that had been wrecked in the rear, the guy who fixed it jacked up all the e-brake equipment, so I want to use all the 4th gen stuff...Can someone point me to the rear info, PLEASE???? Thanks for documenting all your hard work for the rest of us to use....

alacran

Final product, went with C5 calipers. Apparently, autozone C5s don't say "Corvette" on them. Feel great. Thanks for the help.



Nick

zenish

i hope the the brackets i got got from ed this week don't have this problem....

Craig84Z

iTrader: (2)

Alacran,
Why do you have so much space between top of tire and fender?

chevyowner02

iTrader: (3)

I am going to guess that there is no motor in it.

cowansauto

iTrader: (2)

Is the newest, improved design the first one on this page?
http://lukeskaff.com/?page_id=355

89 Iroc Z

Yup!

zenish

i had my hubs made today.only 40 dollars.i will attempt to finish it this weekend.

IROCgiraffe

iTrader: (3)

Where did you take your "donor" hubs to have them cut down/machined to fit the replacement rotors?

zenish

b&b industries in indian trail nc.704-882-4688.its a machine shop.does it matter that my rotor isn't perfectly centered in the adapter since the caliper is floating?i could shim it but id rather have the bracket hard against the adapter.

87350IROC

iTrader: (2)

Functionally it will not be a problem as long as the offset is the same at both ends and the offset is not major. The biggest risk would be dragging brand new pads.

zenish

i managed to buy some fender washers that got it pretty close to center.the problem i have now is my craigslist calipers didn't come with banjo bolts.of course the 1989 banjo bolts are different.i haven't found a parts store that has them yet.

zenish

do not use the napa 83166 bolts that are recommended in another post.they are too short and will rip out a quarter inch of treads of the aluminum calipers.[ask me how i know]go to advance auto and get the 13912 bolts from the 'help' section.they are the perfect length and go 3/4 inch into the calipers.

85IrocZ-28

Amazing thread, thanks to all that have contributed. I just swapped some PBR's off of a 96 TA (along with backing plates) onto my third gen rear. I am now moving to the front. I have a set of LS1 calipers/brackets/and drilled rotors headed my way that I picked up off of ebay for $103.

I plan to do the mods myself, and make my own brackets with some scrap material. I have two questions:

1- EDIT-Found this info
2- 5/16 material sounds like it is the way to go on my 1985 spindles. That is what I will plan on using unless someone tells me that 3/8 would be better for my application.

Thanks for all the great info!

zenish

i tried searching but i need a new master cylinder.should i get another 1989 mc or a lsi mc?does the lsi master bolt on?

zenish

ok.i searched with google today. and found several posts.imo this sites search engine sucks.im going to find me a 1998 up booster,mc,and prop valve.

Sojer

It does sucks, but u dont need it. I have the 4th gen mc and bb but did not install them I will keep the 3rd gen bb and put the cleaner looking 4th gen mc on. And the stock PV will work I have rear drum PV now I have 4 disk with ls1 up front and man I mean its a night and apple difference yes apple lol they not in the same ball park I also have umi torque arm witch helps. They say the 1LE pv should be used but I will go aftermarket its cheaper and better. (Uglier) I plan on going 5th gen or c6 zo6 my car will be a road corse with some strip potential

zenish

i have lsi disc brakes front and rear so i think a lsi master cylinder is a logical choice.

Sojer

Its the proportional valve will have the effect u looking for not the mc

zenish

yes but the pedal is slowly going down under pressure and i can't see any leaks.

zenish

i tried my spare on today.my car came with a space saver spare.it clears my front brakes using my 1.75"spacers but im going to need at least a one inch spacer for the back.i also tried a doughnut spare but it hit front and back.

AUZ28

Hi there, been reading this thread and other ones looking for some answers but don't think I have found them. So I'm looking for anyone who has tried or can test fit my proposed brake upgrade.
First up I'm from Australia so none of the parts I want to try are readily available and I don't want to spend a fortune buying parts just to find they don't fit.

Car - 87 Z28
Rims - 88 16" Iroc (pretty sure that's what they are) double stripe ones

I know the Ls1 rotor, abundment bracket and caliper will fit these rims.
I know the C5 rotor, abundment bracket and caliper do not fit. ( due to caliper fins hitting rim?.)

My proposal is based around the fact that C5 brake pads were used on local Holden Commodores(HSV models). So brake pads are cheap to replace.

I would like to run this combo C5/Ls1 hybrid

Rotor - C5
Abundment bracket - C5
Caliper - Ls1
My thought would be the Ls1 caliper might not hit rim due to the lack of ribs on caliper. As I don't have any parts to play with this is a guess. Can someone without any doubt prove this to work or not!

Or can this work?
Rotor - Ls1
Abundment bracket - C5
Caliper - either Ls1 or C5

Third option that I doubt anyone has any idea of working and is pretty much a gamble is
Rotor - C5
Abundment bracket - C5
Caliper - LOCAL COMMODORE CALIPER (the one picture on page 4 of this thread) I know that the caliper slide pins are the same width and would fit the Ls1 and C5 abundment brackets
If some one can measure the distance between the caliper slide pins and the top of caliper on a Ls1 caliper and a C5 one, I might be able to figure out if they would work.

If all else fails I guess I'll just go for the complete Ls1 setup, but would have loved to try to use the C5 pads as they would be cheaper/easier to replace and keep shipping weight down from all the stuff I'll need to buy.
Any help here would be awesome.

IROCgiraffe

iTrader: (3)

Someone will chime in I'm sure.... But from my readings here... your 2nd option

"Rotor - Ls1
Abundment bracket - C5
Caliper - either Ls1 or C5"

should work with the 16" wheels. I plan on keeping my 16" wheels also, but replace my front calipers with the Corvette raised letter calipers and LS1 rotors to make it all fit

BadboiJR13

Okay brothers help me out,
I have a 88 iroc z with stock rear discs and i want to do the LS1 swap just on front and keep the rear stock, which master cylinder and pv combo would be good for the swap

V6canvas

iTrader: (1)

with the exception of the front brakes, my system is stock, and has been working great for years now.

91banditt2

iTrader: (1)

Back from the dead I know.
Because if it's worth doing it's worth over doing.
My question is if I welded a grade 10.9 12mm nut to the lower caliper bracket mounting hole for more thread engagement will that interfere with other brake or suspension parts?

Strangecars

Can you try to tell me why you need to add the nut or spacer?