|
I would first remove the inspection plate and see if the control rod linkage is still connected like it should be. If it is then they problem may be that the unloading valve is sticking. You need to be sure that the big flat O ring that goes between the backpressure valve and the right side of the lift is good and not leaking when you take the lift off.
Do you know the procedure for removing and replacing the lift in relation to the backpressure valve@ the acorn nut etc.?It is under the big acorn nut that is located on the right side of the lift housing . The nut must me removed and the large hollow stud must be turned at least two complete turn to the left counter clock wise so the the back pressure valve will be clear of the internal lift components when the lift cover is removed. Remove all the linkage to the 3 point hitch so that the lift assembly is free of all attachments. Remove all the bolts from around the outside edge of the lift housing assembly. Do not remove any bolts that are not along the outside edge. If you encounter a bolt with fine threads it should be reinstalled. Remove the 3 bolts that hold the triangular plate toward the front of the lift assembly that is a part of the ram cylinder assembly.
If the lift is not an NAA but a later model
Pull the plug that is over the unloading valve with the threaded hole provided. push the unloading valve out with a punch etc.
Replace the O ring attached with the Ford Part #NCA 836 B or the current replacement number O ring and nothing else .Not a parts house O ring. You will be sorry!
Polish up the unloading valve with 180 grit paper and hone out the bore with the same on a pencil or dowel wrapped with sandpaper.
Examine everything for missing bolts or pins and linkage hanging loose etc.
Closely examine the cam follower pin for excessive wear. The cam follower pin is the main thing that caused the lift to not attain it’s maximum lift height. If it is worn replace it. The cam follower pin is a common hardware dowel pin 5/16" X 1" and can be bought at an industrial supply.
Name: ZANE
E-Mail: wzsherman@aol.com
Subject: Re: Ford 600- Lifting
Body of Message: There is a cam attached to the rocker shaft that is inside the lift housing.This is what the outside lift arms are attached to.The ram rod for the lift cylender's rear end is attached to the lever cast beside the cam.There is a cam follower that is pressed into the control linkage.It is a pin of approx. 5/16" diameter and one inch long.There is no lubrication at this point in the lift and the pin wears out causing the gradual lose of adjustment travel.The pin must be replaced and the linkage re adjusted as per specifications which I don't know off the top of my head and which usually takes a feeler type gauge to measure between the control valve head and the cylender housing where the control valve goes into the spool in the housing. Now is definately the time to replace the cam follower pin. That much wear does make a lot of difference in how the lift works and when it starts to lift according to where the lift control is positioned.
I would defininately obain the correct part to replace it with.Don't go with a cut off bolt etc. as it will wear down too quick.If you are going to consider using a bolt etc you may as well leave the old pin in place because with it worn half way into it out last a bolt etc.
I shouldn't tell you this ,but I have used and ole valve stem by grinding off a piece of proper length.The repalcement is a hardened pin and it has to be hard to prevent rapid wear.Their is no lubrication to the pin. If you foolishly decide to use a valve stem it should be measured with a micrometer to assure the right diameter.If it is a couple of thousands too smalll it may fall out and if it is too large you will ruin the hole it goes in,then the right pin will fall out. Be sure and support the linkage as close to the pin hole as possible while driving the pin in or out.You can do this by holding a long heavy flat ended bar by the pin as it is driven out with a punch of correct diameter. Usually takes two people to do it. One to hammer and one to cuss.
| 
