Mcgaughy drop spindle - Impala Tech
Brakes & Suspension Conversion Questions & more

  • 1 Post By Big Dave
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post #1 of 6 (permalink) Old 10-18-2019, 07:08 PM Thread Starter
Join Date: Oct 2019
Posts: 9
Mcgaughy drop spindle

I have a 65 Impala and it currently has disc brakes on the front. I bought a Wilwood kit and was gonna change em out.

When I pulled the brakes off, I discovered an aftermarket drop spindle so my Wilwood kit would not mate up. I had to return it.

I called Mcgaughy and they said the only caliper that will mount to their spindle is a 79 Monte Carlo caliper.

My question, will a Wilwood kit for a 79 Monte Carlo mount up?
Chris Norris is offline  
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post #2 of 6 (permalink) Old 10-19-2019, 01:46 AM
Join Date: Jan 2006
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Yes it will. 1978-'88 G-body Malibu and Monte Carlo used smaller than the earlier Chevelle's SAE calipers. These metric calipers and rotors are used in most aftermarket disc brake conversions kits because the parts are plentiful (making them cheap). The G-body shares a lot of parts with the earlier A-boy Chevelle but the cars shrank in size to improve mileage. By making a car smaller it becomes lighter. A lighter car isn't a great choice for brakes if you have a heavy full size car. The brakes got smaller because there was less weight to drag to a stop from highway speeds.

Speedway sells a cheaper than Wilwood or Baer caliper alternatives for circle track racers that also fit your existing drop spindle.,25158.html

This yields a better caliper on par with the earlier Chevelle, but you still have the thinner lighter rotor that will fade faster than a larger thicker rotor will (with brakes you want weight to act as a heat sink). More metal means it can absorb more heat before brakes fade. This is why the Corvette uses 13.4' inch rotors (the JL6 option used on the Z05 model moves the caliper out closer to the edge for more are per revolution) that are a quarter inch thicker than the Impala rotor (1.26" vs. the lighter 0.875" Impala rotor thickness).

With Brakes and engines bigger is better! But only you know how you will drive your car. Is the heavier duty Wilwood or Baer unit worth the extra money knowing the G-model brakes are only marginally better at brake fade than the stock drum brake.

Another alternative is to use the C6 Corvette Steering knuckle and spindle on your Impala:

Then you can use stock Corvette rotors and calipers (which requires larger diameter wheels to clear the larger diameter rotor).

Another alternative is the 1977-'90 Impala 9C1 Police front steering knuckle (also used on the station wagon). It has a 12 inch rotor that uses the same smaller metric caliper but it is mounted further out for better stopping. This rotor requires 15 inch vented Police steel wheels that are stronger than stock steel wheels (but are also heavier).

Big Dave
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post #3 of 6 (permalink) Old 10-19-2019, 11:04 PM Thread Starter
Join Date: Oct 2019
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Thank you, sir. Very detailed and helpful response!
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post #4 of 6 (permalink) Old 10-20-2019, 09:20 AM
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Or, you can give Tobin a call at KORE3. He makes C5/C6 brake kits and hubs. Even if it's not listed online, he may have a kit that works for your application. The guy really knows brake setups and will point you in the right direction.

1969 Imapala convertible build thread here:
justjohn is offline  
post #5 of 6 (permalink) Old 10-20-2019, 01:03 PM
Join Date: Jan 2006
Posts: 12,521
Corvette uses a tall spindle just like the Impala which is why it is so popular on first gen Camaros. A tall spindle (or using an over long ball joint to raise the upper A-arm) corrects the steering geometry issues found on the first gen Camaro and 1968-'74 Novas.

The reason no one lists the Impala on their web sites is because the Impala is heavier than a Camaro or Chevelle it's ball joint shafts are larger in diameter for added strength. But like the common problem of the use of a 1350 pinion in-put yoke on your rear end combined with a 1310 drive shaft: there are adapter ball joints in the aftermarket to fix this problem. Similarly there are aftermarket ball joints sold to fix this issue with a smaller ball joint that bolts to the Impala A-arm.

Personally I would just machine the Corvette steering knuckle to accept the stronger Impala ball joints with a tapered reamer in a vertical mill.

Big Dave
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post #6 of 6 (permalink) Old 10-23-2019, 09:07 PM
Join Date: Nov 2018
Posts: 3
Why not just buy a set of drop spindles that work with the Wilwood brakes. I have them on all four corners and love them. All this make a corvette spindle work after machining is silly. Put parts on your car that you can order and replace. Machined parts are not easily duplicated, especially on the side of the road.
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