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10.5" disk brake kit (Kit #307) from Autocity and/or ABS Power Brakes

7.5K views 13 replies 7 participants last post by  Rick_L  
#1 · (Edited)
I'm in the process of installing a #307 Kit (purchased from AutoCity, but seems to be the same kit as the ABS Power Brakes kit #307). I purchased this kit as a means to upgrade the braking and hopefully to allow continued use of my 14" stock wheels and wheel covers to maintain the 'original' look.

In my efforts so far, I've come across a number of issues, and would like to hear from others who have installed this kit. Please comment if you have first hand knowledge/experience with this kit.

Thanks,
 
#2 ·
No responses on my post so far, but I want to add some more detail and see if it elicits anyone's comments.

This kit includes a two piece caliper bracket which mounts only to the two holes at the bottom of the spindle. One piece mounts to the spindle, then the other piece surrounds the back side of the spindle and attached with two bolts to the first bracket (see photo).

The ABSPower instructions state that the brackets can be mounted with the caliper forward or rearward of the spindle, and they can be... until it's time to mount the caliper. Because of my intention to install a CPP front sway bar, I mounted the brackets for a rear mount caliper, and found that the caliper had a slight interference with the steering arm. I'm considering doing a little grinding on the caliper to address the interference; has anyone done this before and what was your results?

I also have some concern over the bracket mounting only to the two lower spindle holes, but I think most aftermarket caliper brackets only use two holes (such as the speedway kit on my '56 Nomad - that I did have issue with), so maybe it's not an issue if properly installed?

Comments appreciated..
 

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#3 ·
Hi Gary,

No experience with your particular kit, but the mounting points don't bother me much. If you think about it, all the forces acting on the calipers will be rotational, not lateral. If anything I would use grade 8 bolts if they aren't already supplied.
 
#5 · (Edited)
After trying to mount the calipers to the rear of the wheel, I finally decided the 'alterations' were too significant, and mounted the calipers to the front of the wheel. Seems it will work in that position, and I'll have to check if the sway bar will work with, or interfere with, that configuration later..

This system came with an 8" power booster and a dual MC with a proportioning valve. Unfortunately, it seems the combination booster and MC would like to occupy the same space as the original generator, so I'm considering just using the MC in a manual configuration, but.. another issue I'm not familiar with and hoping someone here can educate me a bit on this.

The original manual MC is a 'deep throat' MC, ie. the rod goes into the MC approximately 2-5/8", which pretty much makes it impossible for the rod to slip out of place. Unfortunately the replacement dual MC is a shallow throat (approximately 1/4" deep) or 2-1/4" less than the original MC. Of course the factory brake actuation rod is too long to be used, but of course could be shortened, and replacement (adjustable) rods are included in the brake kit, BUT... I'm concerned with the possibility that with this shallow throat MC, the rod could come out, or become jammed which could prevent proper braking operation in some situation. Has anyone investigated or solved this issue? or otherwise can educate me on the issue here? Should I purchase a different (deep throat) dual MC for use in this manual application?? or ??
 
#6 ·
#7 ·
Thanks. I did inquire with Jalapeno and got the information on the bracket he makes which rotates the generator into another position. I'm just looking at my alternatives right now, and I would have no issues with 'manually operated' brakes, IF the dual MC I got in the kit would work. I'm not sure it will due to the 'throat depth' issue; it may be that the shallow throat depth should only be used with the power booster? Hopefully someone had faced that issue and can enlighten me as to this possibly being an option.

PS: The attraction to me of eliminating the booster is that with only the dual booster being the 'mod' under the hood, the underhood would appear very close to 'factory original'; with the booster, that goes out the window.
 
#12 ·
Like BamaNomad . . . .

I used the autocity disc kit and, like BamaNomad, I had to mount the calipers to the front. Simply no way for the steering arms and caliper to occupy the same space. I was wondering if anyone had used a sway bar with this setup and, if so, which one. It looks doable, but close. . . .

Thanks,
John
 
#13 ·
Not using the upper 5/8" bolt is not a good design. Under hard braking all the force is concentrated at that mounting point which is why a 5/8" grade 8 bolt is used, the shear force is very high. The smaller lower bolts will probably hold up but it's iffy. I imagine the only reason for this kit is to clear original 14" wheels, if you have larger wheels I would definitely use a better and safer designed kit.
As far as the master, a deep hole is a must for manual brakes. In my opinion 1" bore for manual is best, 7/8" is too small with large bore calipers and will travel too close to the floorboard for my taste. The smaller the master bore the higher the pressure but more pedal travel is necessary to accomplish the required work. The normal tilted booster bracket that most vendors seem to sell will clear the orig gen/PS set up, no need for "special" brackets.
 
#14 ·
One way to get a dual master cylinder that will fit with the p/s pump is to use a 1" bore master cylinder from a 67-69 Camaro/Chevelle/Nova. It will have a deep cup and is shorter than GM disc/drum or disc/disc master cylinders.

This master cylinder will have two small reservoirs rather than one large reservoir/one small reservoir or two large reservoirs. The downside to that is that as the brake pads wear, you will have to add fluid. Also if you push the caliper piston back when changing pads, it will overflow unless you remove some fluid first.

If you end up using the calipers in front and add the sway bar too, watch to be sure that the calipers don't hit the sway bar when you turn the steering sharply. When the caliper hits the sway bar like that, you'll have a low pedal the first time you apply the brakes and that may not be pretty if unexpected.