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[SDMGC] Front Shocks 66B Hints?
I just received two rebuilt front shocks for my 66B from newsletter advertiser, Apple Hydraulics (old ones are leaking). I also received replacement bushings. From Moss, I ordered two rebound buffers, 8 mounting bolts and cotter pins.
Before I attempt to replace the shocks, I wanted to ask here for any advice or hints on doing this.
Re: [SDMGC] Front Shocks 66B Hints?
It isn't that hard to replace MGB front shocks (or even springs). The springs don't hold a lot of tension like on some other cars so it isn't dangerous.
I'd jack the car up and put axle stands under the spring / on the lower wishbone pans. This will use the weight of the vehicle to keep the springs compressed, assuming all you're planning to do is change the shocks. I like to have at least the two axle stands and maybe the floor jack already in position and taking a little of the weight as insurance.
Then remove the cotter pin/castle nut from the shock / upper mounting pin. To get the shock off, you probably just need to drift the old (keyed) fulcrum pin (moss #263-440) out of the joint and use a lever to pry the arm off of the joint. Then you can remove the 4 bolts that mount the shock to the crossmember.
With the shock off, you can carefully support the disk brake / axle, etc. so it doesn't mess up the brake flex hose. You can now replace the bump stops.
Are you replacing the rubber bushings (moss PN #282-305) that go into the upper trunnion (the metal part that is bolted to the kingpin vertically and to the shock horizontally)? I think you should, they often split.
With new rubber bushings, you might think it is impossible to fit the shock to the trunnion. There is a bolt that holds the two lever arms together (about 1/2 down the arm). Remove that. Then one of the arms is held onto the shock pivot by a bolt. Remove that (don't just loosen it), and you can use a rubber mallet to remove the shock arm from the shock. You'll see that there is a keyway for the bolt at the pivot.
Now here is a point people may agree or disagree with. I loosely bolt the shock to the cross member and get all 4 bolts finger tight. There is some slop in the holes and the shock can turn a couple of degrees. So I get it on, but loose, and then attach it to the upper trunnion. Others may think you bolt the shock down tight first (before installing to the trunnion) or last (after installing to the trunnion). The manual says "installation is the reverse of removal" which measn to tighten the shock down first. You may want to grease (copper grease preferred) the bolts first to help keep rust away. The engine leaks don't really protect these bolts that well!
Put the new bushings in and bolt the arms around the bushing. You have to install the bolt that joins the two arms, tapping the removable arm back on to the pivot. When you get that bolt tight, you should be able to re-install the shock arm bolt back onto the pivot. You should probably play with one of your old shocks before you fool with the new ones. A little grease on the pivot will help.
When the shock is back on the trunnion, you torque the 4 mounting bolts down.
|I jacked up the car using the cross member under the engine. I removed the wheel. I put a jack stand under the lower control arm and then lowered the car enough to get the shock arm about 1 inch above the rubber rebound buffers. I then put a jack stand under the engine cross member.|
|Here is the shock arm
and the connection to the trunnion using a fulcrum pin, slotted bolt
and cotter pin. First remove the cotter pin. (You can see oil from the
shock had spilled all over the front suspension. I cleaned this up as
well as I could before I continued work.)
On the driver's side, it took me 3 days to replace the shock. Not because it was hard but because I had to learn the techniques of using a rubber/plastic headed mallet to get the parts apart. I didn't take any photos then of this side. The remaining photos are then of the passenger side which was not leaking.
|Remove the cotter pin and slotted bolt from the fulcrum pin. I loosened the bolt holding the two arms of the shock together, this let the arms spread just a little to make the next steps easier.|
|Start to remove the fulcrum pin using a plastic headed hammer. Be careful that you don't mess up the threads on the fulcrum pin (unless you are going to replace it). I left the slotted nut on the bolt to protect the threads as long as I could. I used a large drift pin once the bolt was inside of the trunnion.|
|Its on its way out.|
|Once the fulcrum pin is out, use a prybar to remove the shock arm from the suspension link trunnion.|
|I used a block of wood to support the axle. Be careful not let the axle tip over and put excessive strain on the brake line.|
|I removed the four mounting bolts and took out the old shock (passenger side non-leaking shock).|
|This is one of four bolts that holds the shock on to the frame of the car. I had ordered replacement bolts from Moss but they sent me the wrong parts. The original bolts were good enough to reuse.|
|This is the fulcrum pin and slotted bolt. Note the bolt's head. This must fit in to the shock arm correctly.
|Here is the new shock ready to install. I placed it in the car and put in the four mounting bolts. I did not tighten the bolts down completely.|
|I used the fulcrum pin to turn the trunnion to line it up. I then removed the pin.|
|And after using the handy rubber mallet, the shock arm slipped over the trunnion. I installed the fulcrum pin and the the slotted nut.|
|Here you can see the how the head of the fulcrum pin fits onto the shock arm.|
|I tightened the slotted bolt and installed the cotter pin. I then fully tightened the four bolts holding the shock to the frame. I reinstalled the wheel and removed the jack stands and lowered the car to the floor.|
Re: [SDMGC] Front Shocks 66B Hints?
Thanks for the hints about replacing my shocks on my 66B. Replacing the first one took 3 days, the second took 1 hour......
My problem, as usual, was lack of experience. Replacing the first shock was the learning experience. Understanding how hard to bang on the fulcrum pin to remove it and how hard to bang on the shock arm to get it over the bushings was key. A plastic/rubber headed hammer was important here. I did not remove the arm/shock pivot bolt as Andy suggested. Apple Hydraulics had attached a big warning note to the shock arm to NOT remove the bolt. As it turned out, I was able to get the arm over the bushings without the need to remove the arm/bolt.
A question - Since the shock itself is the upper control arm of the front suspension and it certainly seemed like the new shock arm changed the geometry of the front end, is it necessary to get a front end alignment now?
Re: [SDMGC] Re: Front Shocks 66B Hints?
When the suspension is rebuilt to stock specifications and in place, the only alignment adjustment is the toe-in, which should be about 1/16". Of course you can always use negative camber A-arms and offset bushings, but that's more for autocross and racing.
The stock suspension is really quite good for a street car of this era.
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