markk900

Some of you would have seen my earlier post about the 1950s Paff I acquired this week. Disassembly has gone extremely well, considering the age and that its been sitting for several decades. The seat post came out fine; the cotters came out with only a little bit of pressure from the C clamp, bottom bracket came out fine (and in great shape) and almost all the nuts and bolts, though a bit rusty, unthreaded fine.

Except: The stem is stuck in the steerer. I have done all the normal stuff (the expander plug is free, tried twisting, sharp smacks with a hammer to loosen rust, etc), and am currently letting the frame sit upside down for a few days with the stem and steerer full of penetrating oil.

Both stem and steerer are steel, so either its rust or a mechanical issue, though the expander plug came loose quite easily.

Most of the interweb advice follows the same pattern, and I am at the last stage before most of them say "cut the stem off and disassemble" (including Jobst Brant on Sheldon's site).

However, one of the unique features of this bike is that the handlebars, levers, and stem are all one piece, with a lovely Paff plate on the top of the bars. I'd really rather not cut the stem as I will not be able to replace the bar/stem combo without losing this historic feature.

First question - any other suggestions?

Second question - was thinking of rigging up a "reverse press", that would push up from the fork crown through the handlebars with a set of large bolts to apply pressure. Does this make any sense? Could this harm the fork crown?

Third question: I was thinking that if I had to cut the stem, I would do so 1" below the handlebar junction, and then after removing the remains have a welder make up a new section that uses the 1" of cut as overlap so I can retain the bars (but lose most of the adjustment range). The stem is 22mm so seems pretty standard. What are the collective thoughts about that?

It may be moot - after 2 or 3 days of soaking it may come apart on its own, with some persuasion (I hope).

Mark

eschlwc

2 or 3 days? nah. give it weeks or months to soak.

i'm batting 1000 with my four stuck stems. i used equal parts atf/acetone and let them sit for two weeks at a time before trying to remove the stem. if they didn't come free, i gave them another two weeks.

for one of these, i got impatient and used freeze-off after draining the atf/acetone mixture ... which thankfully worked. i put a hardcover book on top of the stem and wacked it with a heavy rubber mallet.

of course, i haven't ever had a bike as old as yours.

hang in there. i would give it months to soak if needed.

miamijim

Heat the stem with heat gun. Be careful because it'll burn paint off.

3speedslow

Dang, I hope it works too ! I would not stop at penetrating oil. Go on to the other choices out there. That stem must be saved.

Consider this a long term project if that's what it takes.

mechanical means would be a choice too. One member rigged up a device which he used to remove a Seatposts. Sort of a slam hammer with plug on one end of a long bolt and a handle to pull up on. I am not describing it well. hopefully someone more familiar with it will chime in.

Good luck ! Let us know how it is going.

nlerner

I have found that the combo of penetrating oil (I also use ATF/acetone), heat, and force will eventually do the job, but you need patience. You also need good leverage. Are you able to get the fork crown in a vise and then twist the bar/stem combo?

daf1009

I have no methods to add....but...encourage the patience...on a bike like you describe...maintaining all of the original you can is cool!

dddd

As nlerner's post suggests, the crown must be held stationary when applying twisting force, or else the dropouts may be weakened or broken outright as the twisting is not resisted solely by back-and-forth forces at the dropouts. I've seen dropouts weakened to the point of failure during a twisting session, but worse yet would be dropouts only weakened, left to perhaps fail later while the bike is being ridden.

Is the stem steel or aluminum? There are products specifically for breaking rust-only bonds, but which will not soak in after other penetrants have already saturated the joint.

I agree with others that a lengthy soak usually helps, and that at some point heat would also help to loosen the grip.
By heat, I mean considerable heat, sufficient to get some oil residues smoking slightly.

michael k

Both stem and steerer are steel,

Give it an AO bath also since both are steel.

SquidPuppet

This might work if the fork has a hole under the crown to accommodate this technique.

Find a LONG bolt (long enough to enter vertically from below the fork crown, pass through the steerer, and pop out the top quill hole) of the same OD as the quill bolt. Jam two nuts together about an inch from the end. Grind the nut ODs so they are small enough to fit inside the quill, but stop when they top out at the bolt hole. In this position, the bolt should be long enough to protrude a couple inches from below the fork crown, between the blades. Use the bolt as a punch, SMACK the bolt head to drive the stem up and out. Since the contact point for the blows is internal, you'll never see the scarring.

With the penetrating oil it might work. At least it will be a way to generate some significant striking force.

markk900

THanks all for the encouragement and suggestions. All will be considered.
@SquidPuppet: that was my idea too but the expander nut is too large to pull out the bottom of the steerer tube, and obviously gets in the way of passing anything back up to the top of the stem.....I did see a suggestion to ream out the bottom of the steerer to get the nut clear but that's not going to happen anytime soon. BTW for interest sake, this stem does not use a ramped wedge, but a slightly conical steel piece that has a couple of slots cut in it at the narrower end - it is drawn into the quill and expands it, leading me to believe a) the quill has also got some expansion slots, and b) that not only is there rust but sometime in the past 60 years the nut may have been tightened enough to really get that stem in there....
@michael k: is an OA bath going to hurt the bearings at all? I assume not....
@dddd and others - no worries, I am very sensitive to bending the fork blades - remember I am a Peugeot AO-8 owner and those fork blades bend if you look at them the wrong way. On this project protecting the fork is uppermost in my mind.

I am not normally a hugely patient person ("pa, get me a bigger hammer") but in this case, especially since the bike is so sentimental to my coworker who gave it to me, if it takes months so be it.

On another note, I have been carefully removing the paint job that was added in the 70s, and to my surprise and delight the bike was quite striking when new: a deep, dark green for the whole bike, with turquoise used for the head tube panel, a section of the seat tube, and for the ends of the forks. No decals here - all colours including the gold pinstriping was painted on. It will (eventually) be a real looker!

SquidPuppet

Duh. I never thought of that. Dunce.

markk900

Not at all - most of the stuck stem sites tell you to pull out the expander, and in the case of the wedge type they are much smaller diameter than the steerer.....great minds were thinking alike; I have the advantage of already having tried to get the nut out and having been thwarted....

michael k

@markk900

My experience with OA it only affects rust (iron oxide) and galvanized surfaces (zinc) not the steel surface thats still intact and not effective on surfaces coated with grease or oil.

nlerner

I made that mistake some time back on a Raleigh Super Course with a stuck stem. I held the stem in the vise by its sides, installed a wheel in the fork, and then tried torking the wheel. Here was the result:



Ends up there was very little brazing material holding that dropout to the fork blade. A local frame builder brazed it right back on (and re-brazed the other side for good measure).

Wanderer

Assuming you have loosened the threaded portions on the top bearing......... right?

markk900

Absolutely! But good to check!

markk900

Update: partial success!!! After letting it soak for several days upside down with the stem and steerer full of penetrant, I flipped her rightside up again, and started soaking from the top. Tonight I applied some heat (with a propane torch), and then tried driving the stem down (while chocking the bottom of the fork crown with a piece of wood so that the force would transfer directly to the floor). After a number of pretty hefty whacks, I saw that the stem had moved down about 1-2mm. So its not completely frozen!!!

I then tried putting the fork crown in a vice (protected by wood), and then twisting the bars....no movement. So its back to where I was, and soaking in more penetrant (I went to the seafoam penetrating/rust remover product).

So if I understand the process (and science) correctly, the stem is not completely stuck, but there is still enough friction to prevent twisting. Would my best course of action to be to continue to drive the stem down to break the rust bonds more, or do I now try to drive it up? I expect twisting would not move my case forward at this time.....or, do I soak longer and hope that the breaking of the bond so far will allow more penetrant in via capillary action?

If the option is to drive the stem up, and suggestions on how to do that since I can't get to the top of the quill (the expander nut is still in the steerer, but loose)....

Chombi

Uhmmmm..... did you try freezing the stem with some "Freeze-Off" Spray penetrant??
Much less possibility of damage compared to heating....
If you use the Freeze-Off correctly, it can break corrosive bonds between parts very quickly, per my experience, like in seconds, in some cases.....

Ed.

Back in the olden days I had ready access to liquid nitrogen. It could work a treat on these sorts of problems.

markk900

@Chombi - I'll give it a try!

I was very careful with the heat....parts were hot but no paint damage and it did seem to help break part of the bond......

dddd

The stem will come out, and a couple of extra days will help the penetrant do it's thing.

I always use a chunk of dry ice to freeze the aluminum post or stem before giving it the mighty nudge with the best tools that I can come up with to encourage movement.

Handle the dry ice with gloves AND a towel, and hold it hard against the aluminum for at least ten minutes, until heavy frost is showing even on the surrounding (headset in this case) parts.

A very good sized chunk of dry ice is just a couple of dollars at the supermarket.

Joe here can testify as to the most stubborn of seatposts and stems that finally yielded to the freeze. Alternating with serious heat can only help the process along, but until the parts are cold, don't bother applying force since the heat temporarily increases the interference pressure that is holding the parts together.

Vinnems

I second the idea of dry ice or other means of freezing the stem. When I was into restoring cars, I would leave bearings in the freezer and leave the part its going into out in the hot sun, and in many cases, the bearings would drop in or require very minimal force to press in. No hammering required. Other mechanics accused me of witchcraft, I just said it was basic science.
Good luck!

3speedslow

Remember, both stem an HB are steel. Freezing works cause there is a diff in shrinkage rates of alloy and steel. Steering tube is steel as well.

crank_addict

Removal of stem on a steel classic

Chombi

That is why one will have to try and freeze just one component and not both. There should be still enough differential shrinkage before the freezing temperatures crosses over from the stem to the steerer tube, especially if there is some layer of corrosion or in some areas, a thin air gap acting like a slight thermal break. If a first attempt is not successful, a few cycles of freezing/thawing and re-freezing should do it.