LS1 front brakes on G body spindle

roger1

roger1

Greasemonkey
Aug 23, 2010
226
155
43
San Angelo, TX
#71
I can get into mine tonight if you want PM me about 7 to remind me, I just have to pull the caliper off so I can pull the rotor off.

Seems like depending on who you get at wilwood they either read off the website and tell you what you already know or will get your info and give you a call back with an answer.
Thanks but no need. I just heard back from Wilwood and the OD is 5.96". About .09 too big to fit the LS1 rotors.
I have to weigh my options now.
I'm reluctant to try and have another set of stock G-Body rotors cut down into hubs.
 
roger1

roger1

Greasemonkey
Aug 23, 2010
226
155
43
San Angelo, TX
#72
The part number in the kit is 270-11043
My kit is 140-12837.
I might have to think about this kit. If I went with it, I'd need new spindles. The mods I made to the spindles I have for the LS1 brakes make them unusable for this Wilwood kit.

Question for you though.
Wilwood recommends a machine shop to so the spindle modifications they specify in their instructions.
They are pretty specific about the countersink on the holes you have to drill and tap in the spindles.
How do you intend to do this?
 
MC96

MC96

Greasemonkey
Dec 7, 2015
235
99
28
#73
.045 off the radius?


Id turn them and not think twice
 
roger1

roger1

Greasemonkey
Aug 23, 2010
226
155
43
San Angelo, TX
#74
.045 off the radius?
Id turn them and not think twice
True. I wasn't thinking radius so it's half as much as my first reaction.
I could probably mount them on the spindle and rig up something to spin them and cut with sandpaper seeing on how it's aluminum.
 
MC96

MC96

Greasemonkey
Dec 7, 2015
235
99
28
#75
Something like that I make a mandrill for and thread a bolt through the hub to cinch it to the mandrill. Maybe use he hub seal register on the back to center on the mandrill and a bearing race driver drilled through with the bolt size to register the outer par of the hub. I wouldnt clamp directly on it, you probably cant with all the draft angles they machine into them
 
Northernregal

Northernregal

Master Mechanic
Oct 24, 2017
311
553
93
Red Deer AB
#76
I might have to think about this kit. If I went with it, I'd need new spindles. The mods I made to the spindles I have for the LS1 brakes make them unusable for this Wilwood kit.

Question for you though.
Wilwood recommends a machine shop to so the spindle modifications they specify in their instructions.
They are pretty specific about the countersink on the holes you have to drill and tap in the spindles.
How do you intend to do this?
If it has to be machined I’ll get a shop to do it. Not a big deal. If I can’t do it myself.
 
roger1

roger1

Greasemonkey
Aug 23, 2010
226
155
43
San Angelo, TX
#77
Something like that I make a mandrill for and thread a bolt through the hub to cinch it to the mandrill. Maybe use he hub seal register on the back to center on the mandrill and a bearing race driver drilled through with the bolt size to register the outer par of the hub. I wouldnt clamp directly on it, you probably cant with all the draft angles they machine into them
I was thinking more along the lines of using a fan belt around the hub snout and a motor shaft on my bench grinder or metal polisher. That should spin it pretty well.
 
roger1

roger1

Greasemonkey
Aug 23, 2010
226
155
43
San Angelo, TX
#78
Rotors are made a bit wavy (I forget the amount but its in the .005ish range if I remember right) to "force" the pads away from the rotor to reduce friction. If the rotor was 100% parallel and flat the pads would always slightly drag on the rotor, the bit of wave pushes the pad off a few thousands, and you never feel it in the pedal.
It is tough to convince your mind that it is OK, but if you have the parts, it doenst take long to swap the hubs over if they do shake. I would put those on, take it for a drive, and if it pedal pulses you have maybe half an hour per side to remove the wheel, rotor and caliper, swap the hub, and put it back together. I would do that just to confirm that .011" face runout is or isnt OK.
I've been thinking more about this. It seems that what the lateral runout measurement is taken from one side of the rotor might not mean as much as I thought. I was thinking in one dimension but it's really a 2 dimensional issue. It seems that it's thickness variations around the rotor that is the important number. It can be assumed that there is zero thickness variation on brand new rotors and a variation there is what you are going to feel in the pedal as a pulsation. If there is no thickness variation then a lateral runout will move the entire floating caliper during braking and not move the pistons in/out at all. If the caliper is moving a little that won't be felt at the pedal. In the case of the LS1 calipers, they float (slide) on a set of shafts that you grease. And even with my worse measurement of .013, that's less than a 64th of an inch. Not very much. I got my feeler gauge out to look at a .013 leaf. It's pretty darn thin.

I just now talked to the machinist I used to flatten these hubs last week and discussed this with him. He said the runout number didn't bother him one bit and I'm good to go as-is.

So, I'm going to assemble them on the car now and hope all will be OK.
 
Last edited:
roger1

roger1

Greasemonkey
Aug 23, 2010
226
155
43
San Angelo, TX
#79
So I finished my LS1 brake installation yesterday and got it all bled and there was still plenty of time for a good test drive.
They are perfect! The feel is absolutely fantastic!

I just posted all my photos on this process of over on the elcaminocentral forum. https://www.elcaminocentral.com/showthread.php?p=2471732#post2471732 I also posted them in my project thread below.

I've already hijacked this thread enough. 81Cutlass, I hope I haven't aggravated you that I've posted so much in your thread. It's been a great help to me and I appreciate it and your help. I've never attempted anything like this before.
 
8

81cutlass

Royal Smart Person
Feb 16, 2009
1,234
1,094
113
Western MN
#80
So I finished my LS1 brake installation yesterday and got it all bled and there was still plenty of time for a good test drive.
They are perfect! The feel is absolutely fantastic!

I just posted all my photos on this process of over on the elcaminocentral forum. https://www.elcaminocentral.com/showthread.php?p=2471732#post2471732 I also posted them in my project thread below.

I've already hijacked this thread enough. 81Cutlass, I hope I haven't aggravated you that I've posted so much in your thread. It's been a great help to me and I appreciate it and your help. I've never attempted anything like this before.
Glad to hear it worked out well for you! It's good the info is here you ran into and although it seems

Just curious, when you had stock G body calipers and master cylinder, was your pedal squishy?

My 2+2 had a soft pedal from the day I bought it. I put disks on the rear, still soft. Went to a caprice master cylinder, still soft. Went to LS1 brakes? Very firm.

Wondering if my experience in the pedal firming up is consistent with other LS brake setups.
 
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