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free seized up forks
Posted: Sat Jan 05, 2019 10:40 pm
by enfield_trials
Hi Guys
I have 1950s bullet frame with front forks seized up. the bike seems to be not have any humanly contact in decades.
this is basically back yard built. so have only basic toolkit in hand.
my idea was to filled the forks with diesel for few days in up side down position.and then may start hitting with mallet
so removed bottom stud nut and put the frame up side down.
the tried to filling it with diesel and it just went to hollow stud filled up quickly.
I haven't tried opening top plug screw .. yet. seem bit seized up as well. I dont have any blow torch or hot air gun to loosen things up
dont want to damage the screw.
appreciate if you better ideas/advice i will try to share some pictures tomorrow ..
Regards
ET
free seized up forks
Posted: Sun Jan 06, 2019 8:47 am
by Mark M
Good idea to fill with Diesel. The snag with filling from the bottom stud is that the narrow hole fills up with dried grease and rust and won't allow much liquid in. You'll have to take the top plug out to fill it properly. Go and buy a MAP (methane and propane) gas torch from a DIY store, not very expensive but in any case having seen pictures of the parts you are working on you will need it more than once, trust me!
REgards, Mark
free seized up forks
Posted: Sun Jan 06, 2019 11:03 am
by enfield_trials
Hi Mark
Thanks for your advice. I agree what you said. i will look for MAPP torch ..
Regards
ET
free seized up forks
Posted: Mon Jan 07, 2019 3:53 pm
by stinkwheel
Once the bottom nut is off, isn't it just rust/seal friction holding it? The bottoms ought to slide-hammer off?
A 50:50 mix of paraffin and ATF makes a good penetrating oil.
free seized up forks
Posted: Mon Jan 07, 2019 4:45 pm
by Mark M
Stinkwheel, I've had this problem with a set of Crusader forks. The alloy internal corrosion expands into the already small gap with the steel stanchion locking the two together. Because you've got quite a lot of contact area and only the top and bottom of the slider to inject lubricant into the gap, it takes quite a while to free the two parts. I found regular sessions of heat to expand the alloy followed by adding as much penetrating oil as would go in eventually freed it. Hitting the slider just damages the alloy and even holding the slider in the vice is tricky as it is difficult to hold a tube firmly. I found re-attaching the wheel spindle clamp and using a half inch bar as a tommy bar helped me to (eventually) get the stanchion turning. Once you've got a little movement it's going to work, you just need patience. I left the two stanchions by the bench vice and gave them the treatment whenever I'd got time left after doing other jobs!
REgards, Mark
free seized up forks
Posted: Mon Jan 07, 2019 6:43 pm
by vince
Hi, you will have to fill these from the top, inverted any fluid will come out through the filter vent. Unlike later forks which are sealed, 1950 forks vent to atmosphere as they operate. Vince
free seized up forks
Posted: Mon Jan 07, 2019 6:45 pm
by gnasher
I have just had the same with my barn find, i fitted a bar to the axle holding clamps and and freed them off, once i got them to spin it freed them vertically as well.