Removing Fulcrum Pins

[Jim_Gruber]

I received new fulcrum pin bushings this morning in the mail from Apple. Look simple to install but bushings have no lip so there is 100% adjustability and they need a fulcrum pin so they can be fitted when they are heated and soldered in place. Note with the bushings said to use an old fulcrum pin as heating one of the new fulcrum pins to solder will take the temper out of it.

So since my method of removing old fulcrum pins consists of cutting out with an angle grinder and a reciprocating saw thos destroying the fulcrum pin, anyone got a good method of getting out an old fulcrum pin. I have a really old bad core I can try on as well as my other good wishbone I am going to rebush. Thinking drill out the retaining pin and with lots of PB Blaster, and use of cutting wheel perhaps I can extrac a fulcrum pin and separate it from a kingpin.

Easiest way may be to simply see if I can get another Fulcrum pin only from Apple. I know Winners Circle sells Fulcrum pin along with bushing set.

Ideas guys?

 

[Jim_Gruber]

A;so, should bushing be soldered in flush with side of wishbone. Looking at the BMC Workshop manual no details are provided for refitting the fulcrum pin bushings. My guess would be to get them as tight as possible allowing room for the cork washers in there.

 

[jlaird]

If you have an old a frame with a bad pin in it use heat take it all out then you can use some serious heat with pipe wrenchs.

 

[HAN5L778]

Jim,
I have several fulcrum pins, both new and used. If you want a used one just pay for shipping and I can send it to you.
The bushing should not be flush with the wishbone. It should stick out just a little for the cork seals to sit on, maybe 1/16" or less.
Is Apple now selling the bushings? I tried them early this year and they said they didn't have any to sell. I buy mine from Winner's Circle and they come with new bushings.
Richard

 

[Jim_Gruber]

Hmmm, Thinking I could use Dremel and cutting wheel to remove all surrounding metal around bushing and then probably unscrew the bushing while being able to hold on to Kingpin. Then cut the kingping, slice into the kingpin and twist it off of the fulcrum and at the same time not damage threads. I see a need already for nuts of the proper size to clean up threads on the removed kingpin. This one will take some definite cogitation to accomplish.

Concern is how to make sure how much end gap is needed from side of kingpin to edges of fulcrum pin when bushings are inserted into wishbone. There is considerable amount of play in there depending on how things are soldered in place. Potentially an alignment issue with kingpin and rest of front suspension.

 

[regularman]

Yeah, use an old fulcrum pin to hold it in place while sweating the silver solder on the new bushings. Pieces of a fulcrum pin are not going to help you Jim. You need a whole one for alignment. Those pins have a 1/2 and 9/16 size to them but both sizes are 16 pitch (if I recall right). Its all got to be screwed together before the soldering/brazing. I don't know if you still have my number but call me before you do this if you have any question at all. Pm me for my nuber if you don't have it.

 

[nomad]

You don't want to use one with much wear. I sacrificed a new pin to do mine because the old pin allowed slop that would have affected alignment. I would recommend plenty of Never Seise on the pin as well and a big stout screw driver to remove it. Course I used brazing to weld mine in.

Have fun! Kurt.

 

[aeronca65t]

Just reading all of this.

Are you guys silver-soldering them in?

I always brazed them in. They look brazed from the factory.

 

[Jim_Gruber]

Rather than try and extract one from and old knackered up wishbone going to see if Apple can supply a new one as a sacrificial pin. Heating I'm told ruins the temper so $15-20 for a pin is a throwaway item compared to the effort to pull this thing apart and redo the bushings. I want to do this right once.

So Kim and others who've been down this road. I know I can't braze or silve solder this in place and get the alignment correct without a sacrificial kingpin in there for correct spacing as well as something to take up the spacing for the cork washers. Thinking I can find some sort of steel washer that could go in there for proper spacing and then take it all apart after brazing. Question is what size and how tight to fit the gaps. The BMC Manual provides no details.

 

[jlaird]

cork washers appear to be about 1/8 inch each. they do not fit tight, loose if anything. remember they are going to be rubbing as the spindle moves up and down so not even snug, loose.


Ever wonder, if I so dam smart how come I'm not rich? Gesh.

 

[Jim_Gruber]

K thanks Jack. Thought I'd have time to extract a fulcrum pin and got old kingpin removed. That process after drilling out pun looks to be an apply lots of heat project and figure out how to pound on the fulcrum pin and at the same time not bugger up the threads. Thought I could get simple nut to fit on there, double nut and twist but based on Kim's comment these may be some oddball British Thread, Whitworth maybe with a non standard pitch. I'll get kingpin and fulcrum pin cut off, soak in PB Blaster, and then try to remove. Will be interesting.

Also, the old bushings are definitely bronze as contrasted to the new steel ones available. Will be interesting to see how these wear.

 

[Jim_Gruber]

One other note for anyone attempting to do this themselves. Wishbones supplied by the usual suspects over the past 7 years or so according to Lazar from Apple Hydraulics are coming with bushings welded in not brazed. You can throw those babies away when the time comes as they cannot be rebuilt.

 

[jlaird]

Wonder if the Heratage ones are as well, that is what was available when I got Miss Agathas.

 

[nomad]

Jim: You need a good original or someone with a new one to give you measurements. I don't think it is awfully critical. I had to do a little work with a die grinder on the holes after I removed the old ones. Probably because the OD on the new was'nt quite the same. I think if you check closely you will see that they are steel and brazed in though a low melting point braze may have been used.
If no one else with better junk than I can help out I'll do some checking tommorrow. May even be able to send you my sacrifice trunnion pin If I can find it. They used to be cheaper.

Kurt.

 

[SilentUnicorn]

Also, the old bushings are definitely bronze as contrasted to the new steel ones available. Will be interesting to see how these wear.

It is unlikely they are bronze- it just would not hold up in that application. What you are most likely seeing is the braze.


m

 

[Jim_Gruber]

Thanks guys, I'll see this week if I can extract a kingpin for proper spacing. Will see tomorrow if Apple can supply a sacrificial fulcrum pin and will have one night this week I can at leadt heat up the torch and see if I can get the bushings out. I'm starting to feel a little like a blacksmith here.

 

[regularman]

Just reading all of this.

Are you guys silver-soldering them in?

I always brazed them in. They look brazed from the factory.

Silver soldering is brazing using silver. I already had the expensive silver solder from when I did refrigeration work, so I used that. Its as strong or stronger than the brazing rod. You got to use a torch with a lazy flame for both of them. Its just what I am used to.
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Brass Brazing

As the name implies, brazing is usually done with a filler made of some form of brass or bronze, alloys of copper with zinc, tin, and other metals. Brass and bronze brazing alloys typically melt at temperatures over 1500F, sometimes as high as 2000F. This is hot enough to anneal steel, destroying any strength added through heat treatment. For this reason, heat-treated bicycle tubing such as Reynolds 731 should not be brass brazed.

For tubing that has not been heat treated, such as Reynolds 531 or plain 4130 chromoly steel, brass brazing is entirely appropriate. It produces joints that are more than strong enough for a bicycle frame, it costs much less than silver, and it is a more forgiving process, allowing wider tolerances in tube mitering and temperature control. The vast majority of brazed production bicycle frames, and a large share of custom frames, are all brass or bronze brazed. Especially for a beginning frame builder, brass is often a good choice.

Silver Brazing

Lower temperatures and stronger joints can be achieved with more expensive alloys composed largely of silver. Silver fillers melt and flow at lower temperatures than most brass or bronze fillers, and are better at wicking into very fine joints. Both of these characteristics improve final joint strength.

Note: While modern U.S. usage calls the use of these alloys silver brazing, obsolete U.S. works and many current British sources often use the terms silver soldering or hard soldering to describe the same process. This is a source of continuing confusion, since silver solder is a term also used to describe much weaker alloys used at low temperatures for plumbing work. To avoid confusion, try to refer to an alloy's composition, standardized classification, or melting and flowing temperatures. When in doubt, seek clarification.[/QUOTE]

 

[aeronca65t]

Yeah, I know the difference between silver soldering and brazing (with a brass-based filler rod). They're both fine for this application.

Just wanted to make sure no one was thinking that these parts can just be "soldered" in place. :wink:

 

[Jim_Gruber]

OK Apple does not sell Fulcrum Pins however another look at the Moss Catalog and there they are Item 12. My sacrificial Fulcrum Pin will be here Friday. No time to get the old bushings out yet.

Hey Kim, PM me with your phone #. Will you be around Saturday AM to chat?

 

[HAN5L778]

I've rebuilt about 10 sets of a-arms over they years so I can speak from experience. Yes, you will probably have to grind the holes a bit for the new bushings. Make sure the new bushings, with fulcrum pin installed, fit FREELY in the holes. If there is any binding when they are installed you will never get the fulcrum pin out after brazing/silver soldering them in. I have ruined more than 1 set of bushings because of this. Also, once you get a small braze on each bushing start rotating the fulcrum pin to make sure it moves. Keep doing this in brazing the bushings in. You don't need to rotate them much, you are just making sure that everything still lines up.
I have also used the new fulcrum pin while brazing, then just cleaned it up after and used it in the rebuild. Yes, some or most of the temper may be gone, but remember that these cars won't be used as a daily driver (at least by most of us) and won't be subjected to rough roads or lack of grease. They should last for many years.
Richard