Perch Bolt Puller Knocker

[C9]

Here's the little tool I alluded to a couple of days back.
Thought it would be finished that afternoon, but there was some running around to find the right bolts and I still haven't got them.
Even so, the build was done with bolts that were too short, but in the size and thread pitch I wanted.  9/16-18 selected for several reasons.  Strength for one.  I've found that pullers of any kind need to be overbuilt to the point of ridiculousness.  As you saw with the "Mongo" puller I built a couple years back.  That thing was seriously strong and was built to accept an eight ton hydraulic jack or a 1" NF bolt to do the pulling.  Interestingly enough, the 1" NF bolt developed more pulling power than did the 8 ton jack.

Since a great many of us are dealing with the solid axle Ford front ends and one of the biggest problems is what should be one of the simplest and easiest to accomplish.  Removing the front spring perch bolts.
I've heard and seen a number of ways to do, some crude, some not.  The most successful methods usually involve heat.  Heat is the answer to many problems and it's amazing what you can accomplish with it.

A friend who's been through more than a few of the old Ford front ends has a "knocker" he made.
A simple enough deal, it's a piece of approx 1 1/4" to 1 ½" round with a blind hole drilled and tapped to 5/8-18 which is the same thread size the perch bolts are.  On the passenger cars anyway.  Trucks may be different, but the F1 size pickups are probably the same size.
Once he gets the usually rusted on perch bolt nut off, the knocker is screwed on, leaving about 1/8" between knocker and bottom wishbone bracket.  You don't want to be too far out or you could bend the perch bolt.  Something I think that could be easily done with a knocker, but he reports it almost always works.  Even so, he's a sensible guy and the knocker with a reasonable application of heat does the job for him.  Hard to argue with success.

My thinking is, for some of the perch bolts - and let's face it, taking them apart after they've had 55 or more years to rust together . . . well . . . it can be a *.

Long as we're on opinions, here's mine on the knocker deal.  Strike something with a hammer and you get a momentary force of more than a few tons.  Specially if you use a BFH which you may as well start out with.  The flaw to the knocker bit is, once the force is removed the rusted together, stuck together or however you want to put it parts revert to their normal status.  Normal status being a particular size and microscopically locked together by the rusted together surfaces of the two parts.  Even so, enough blows, a big enough BFH and enough heat will get most things apart.

That said, here's a puller a thinking person can make with nothing more than a drill press and a welder.  A little tapping and drilling is required, but only once and it's no big deal.
The big deal is keeping everything square.  You don't want to be putting force on a perch bolt at an angle and risk bending it.  If you're gonna do that, you may as well cut it out with a torch.  Provided you can keep from damaging the axle.  It can be done, but takes some experience, skill and thinking about it.

My theory on pulling the usually recalcitrant perch bolts is to put a steady pressure on them and utilize the force obtained from a momentary shock loading supplied by the aforementioned BFH.

What follows is a simple how to do it as well as how it worked out and problems incurred along the way.

This first photo shows the component parts.  The lower piece (base plate) and the two upper bars made from the same piece of 3/4" cold rolled.  The base plate 4" square and the upper bars are 2 1/4" x 4".

[C9]

Pretty straight forward stuff.
Cut the pieces to size.
Lay one upper bar out so there is plenty of room at the ends of the upper bars and the base plate corners for a 9/16" hole.
(Make sure as well that the bolts are going to clear the axle components.  You need a reasonably close fit so the upper bars and base plate aren't so long they are prone to bend.  This distance is not too critical and the puller/knocker I made will probably work on most Ford perch bolts.)

Center punch one upper bar and drill a small hole - I use 1/8".  You only have to go in a little way to set things up for accurate drilling with a 1/4" drill.  Perhaps 1/4" or so.
Through drill with a 1/4" drill on both ends of the upper bar.  (Don't use the next size up drill - 17/64" because you want an accurate fit.)
Mark this upper bar as your "Master" bar because all succeeding measurements and drilling will be done from it.
Line the upper bar up with the outer edges of the base plate so they fit together accurately.
Use a transfer punch and knock a mark in the base plate.
Drill it the same way you did the upper.  In this case, only drill one hole in the base plate.
Go to the diagonally opposite corner of the base plate and drill another single hole.

Use a 1/4" bolt and nut to tie the master upper bar and base plate together.  Align the sides carefully prior to torquing the bolt down.
Clamp and drill through the base plate with a 1/4" drill.
Do the same on the other side of the base plate.

Use your master upper bar clamped in place to drill the 2nd upper bar using the upper bar as a drill jig.
This way, things will fit together accurately and the upper and lower bars will interchange with no problems.
Lotta stuff so far, but it's no big deal and doesn't take long.

Photo 1 also shows the 5/8-18 threaded knocker base for want of a better name.
Note that it has a .125 step machined in, but you can get by without this if you like.

One place that can be difficult for some is drilling the base plate center hole out to 1 1/8" to match the stepped area of the knocker base.
The knocker base is made from a piece of 1 1/4" hard chrome plated shafting.
In most cases, this is quality stuff, machines easy and welds ok in non-critical applications.  Non-critical meaning you don't have to remove the hard chrome for a project like this.  Just weld right over it.

Do note that the knocker base and base plate have a chamfer to accept the weld bead.  A little deeper chamfer on the base plate than shown here would be better.  Especially if you do what I did and grind the weld bead down.  Not much grinding is required since the bead is down in the chamfer.  Fwiw - all welding done by my little Miller 130 amp 110 V welder.  There's also three short and strong tack welds on the underside as a small form of insurance.

A good welder could cut the base plate hole out with a plasma or oxy/acetylene and make sure the knocker base is square prior to welding.

This photo shows the 36 Ford front axle I'm dealing with.  Far as I know it's never been apart.
It fell into my hands due to the typical M2 installation in a 5 window coupe my friend is doing for a guy in the Southland.  Said guy wasn't particularly interested in the "old axle."
Note the thin hex portion at the top of the perch bolt right next to the axle.  I'm guessing this is used at the factory to retain the perch bolt in position as the nut on the bottom side is torqued down.  Noted here because you need to leave room for this hex area as the perch bolt comes up.
If you don't, you'll be pulling and knocking with the puller locked solid top and bottom.

The dark stains are from my soaking the area down with Aero-Kroil for the last three days.  Seems like penetrant - regardless of brand works better over a period of a few days.  I'm guessing the thermal cycles of a few overnights aid the penetrant in doing it's job like it's supposed to do.

XX #2

[C9]

Here's a photo of the completed puller/knocker.
Note the bars are separate on top and they didn't work out as well as I thought they would.  More on that in a bit.

XX #3

[C9]

This photo shows the base plate with it's welded on knocker screwed onto the perch bolt proper.
For the removal process it was spun on much closer to the lower leg of the wishbone bracket.
The farther out it is the greater the possibility of bending the perch bolt.

XX #4

[C9]

Shown here is the puller/knocker mounted and ready to use.
Note as well, the added cross bars welded on.  I found that the free floating bars tended to come toward each other as torque was applied to the four bolts and the bars would have interfered with the aforementioned hex at the upper part of where the perch bolt mounts.
A couple of short pieces were welded in to retain the proper spread of the upper bars.
If I was doing it again, I'd make an upper plate exactly like the base plate and bore the center hole large enough to clear the shock bracketry stuff at the top end of the perch bolt.  In fact, a couple pieces of 3/4 - 1" round plate 4-5" in diameter may be a better way to go.  Live and learn I guess.

It may be a good idea to round the outer part of the upper bars so they don't dig into the wishbones proper as force is applied.  If not, and pulling a light dent into the wishbone is a concern, a piece of .125 aluminum could be used as a pad, but it's probably more trouble than it's worth and a rounded upper bar is a better way to go.

XX #5

[C9]

Here's another view of the puller/knocker set up and ready to go.
One thing you can't see here is the .125 relief lathe cut into the underside of the upper bars to gain clearance for the hex at the top of the perch bolt mount.
This relief could also be ground or filed in.

XX #6

[C9]

The observant will note the puller is equipped with ½-13 bolts and not the 9/16-18 it was designed for.  No one in town had the 9/16-18 in the 7" length required so I used ½-13's for the initial tryout.  The 9/16" bolts are on order and I plan to use those because the close fit of the bolts and the 9/16" bore where they mount will assist in keeping the puller/knocker straight during use.
   
So . . . you're wondering.
How did it work?
I'm happy to report it worked better than expected.  Granted, a bit of backtracking on the way, but that's the way it always goes with something new.

I got the base plate spun on, about 1/8" short of the bottom of the wishbone's lower mount, bolted the four puller bolts on and torqued them down lightly.
I advanced the torque on the puller bolts in even stages - guesstimate only - and once I got them to perhaps 70# torque nothing had moved.
Since the axle/wishbone/wheel combo is not in a car and out in the open so to speak, I tipped it up and gave it about half a dozen whacks on the knocker bottom - using a 4# jack - and it didn't look like anything moved.
I decided to quit for the day and use the torch to apply a little heat tomorrow morning.

Once the wishbones were laid back down I could see a little daylight on one side of where the wishbone contacts the underside of the axle.
Applying a wrench to the bolts on what appeared to be the loose side, I found the bolts were backed off to about 10# or so of torque.
Running the bolts back to 60-70# of torque - evenly all the way around - I was rewarded with those creaking and popping sounds of old parts grudgingly coming apart.
A few more cranks and the base plate bottomed out on the bottom of the wishbone and you could see that things were loose.
I quit at that point since the spring is still on.
So far, so good as the old saying goes.
The perch bolt was loosened without damage and did not require the use of heat.

I think what makes this successful is the constant tension combined with the added multi-ton force of the 4# jack (a jack is a hammer if that's a new one on you).
Once the knocker is struck the tension from the puller doesn't allow the potentially recalcitrant parts to return to where they were and there's nowhere to go but apart.

All in all I'm pleased with the Perch Bolt Puller Knocker.
More than likely it's been done before, but it's all new to me.

Best part is, disassembly is accomplished without ruining any components and it makes a once tough job reasonably easy.

So what - you may ask  - is C9 going to do with a stock 36 Ford axle.
Equipped with 42-48 Ford brakes fwiw.
Not sure right now, but it doesn't hurt to collect parts now for a four cylinder powered roadster that's in the back of my mind and if I'm lucky will perhaps be a future project.
If I ever get moved to Arizona anyway.
I hear the sand washes and desert foothills have early tin lying all about.
What better place for a guy with old thoughts and a new bent....

C9

[Bruce Dorsi]

Interesting and informative, as usual, Sir!


FWIW, the BEST penetrating solvent I have used for rusted parts is Rubbing Alcohol, aka isopropyl alcohol.

I picked this tip up from the antique tractor guys, and it works well for me.

[C9]

Interesting and informative, as usual, Sir!


FWIW, the BEST penetrating solvent I have used for rusted parts is Rubbing Alcohol, aka isopropyl alcohol.

I picked this tip up from the antique tractor guys, and it works well for me.

Thanks.  Was a fun project.

Interesting on using alcohol for a penetrant.
I like Aero-Kroil, but where I live it's only available by mail order.
Some of the guys I know like PB Blaster, but I haven't tried it yet.
Since I keep Rubbing Alcohol in stock - in the garage for cleaning out freshly honed brake cylinders - I'll give it a try.

Seems like good advice.
There are some tractor restoration guys up here - lotsa farms around - and almost always the tractors are a long tough slog when fighting the Rust Demon....

[enjenjo]

I use PB Blaster, none better as far as I am concerned. I never tried it, but disolving a bit of ATF in alcohol should be effective.

Most people don't realise the power of rust. It can create up to 3 million pounds per square inch pressure. No wonder it's so hard to get apart!!!

A little never-seize on reassembly makes it easier the next time.

[purplepickup]

Thanks Jay!  As usual, your post is clearly written, detailed, and easy to follow......AND helpful.  One of my current projects has a freshly assembled tube front end but I recently came across a rusty ford beam axle slated for use in another future project, and I'm sure the perches are firmly rusted in.  

I, for one, really appreciate that you spend so much of your time passing on your knowledge and creativeness.  This post will find a home on my hard drive in the ever growing folder of tech tips you guys post.  I really need to get that stuff better organized and save it to a CD.  I'd lose a lot of valuable info if I ever have a crash.

Thanks again :b-d:

[phat46]

Here's the little tool I alluded to a couple of days back.

 Thanks, this wiil probably come in handy in the future. Like you I am gathering parts for a four banger track T type car. I have the motor/trans and a cowl. I just checked with my brother to make sure he still had "my" Ford axles behind his barn. I know the perches will have to come out of the front axle sooner or later.
 BTW have you tried gun shows for Areo Kroyl? That's where i get mine now since my neighbor who got it for me from the paper mill moved away.