1940 Buick 51
February 2021 - Front suspension rebuild
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The front brake drums are attached to the hub with a large nut secured in place with a cotter pin. Note that the left hand side has a reverse threaded that is removed by turning clockwise. The right hand side nut is threaded normally and is removed by turning counter-clockwise.
A view of the front wheel hub with the drum removed.
To remove the spring-loaded lower control arms, I used the same method as described on the Rover P4 suspension rebuild using a floor jack with a strap to the top of the frame and used the jack to squeeze the control arm so the wheel knuckle could be removed. The top and bottom of the knuckle are held in place by large threaded bolts with grease fittings. There is a photo of the floor jack setup during the front suspension reassembly.
The above video shows the loose king pins on my 1940 Buick and some of the process for disassembly to replace the worn out king pin bushings. The following video for a 1955 Buick shows a similar process and how to actually ream the new king pin bushings. After pressing in the new bushings, it will be smaller in diameter than the actual pins and require reaming to enlarge the bushings to a precise 0.86 inch diameter for the new king pins to fit in snugly. I strongly recommend using a guide pilot in front of the reamer to line it up to both top and bottom bushings unlike in the video. The steering knuckle design is largely the same between 1940 and 1955.
This video for a 1955 Buick shows a similar process for rebuilding the king pins.
I used Mastercoat primer and chassis black paint to repaint the wheel hubs and knuckles then reassembled.
The king pin reamer I used is an old USA made Crichley adjustable 27/32" - 15/16" reamer with accompanying guide pilot that I purchased used on ebay. I have not had good luck with the newer Chinese/Indian-made reamers.
The control arms were filthy and the welded on bracket for the new shock absorber was cut off and removed.
The 1940 series 40 and 50 Buicks had leather bushings at the inner joints of the lower control arms that unfortunately would wear out, become loose, and go out of round from metal on metal rubbing over 80 years. The larger series 60 and up Buicks had much better threaded joints. There was a company at one time that made reproduction control arms, but they were no longer available. I shipped mine off to Doug Seybold in Ohio to mill out and thread my existing control arms to accept threaded bushings like the larger series Buicks. I did not wish to invest in a mill and threading tools to do this job.
Springs were stripped and then repainted with Rustolem primer and satin black enamel rattle can paint.
The upper lever action shock dampers were sent to Five Points Classic Auto Shocks in California to be rebuilt.