In detail: DIY repair of a bicycle fork zoom from a real master for the site my.housecope.com.
→ Pieces of iron and equipment → Vel.kom. Bicycle mechanic's notes # 3. Reviving and improving the Zoom fork.
Pages 1
You must login or register to post a response.
Nefelim
Bicycle workshop Vel.kom. Dikopoltseva 48
Inactive
Where: Centre
Registered: 21-04-2010
Posts: 5,600
The patient was admitted in a “colum” state, i.e. the plug did not work at all, everything was covered with sandy-solid filth, and it smelled quite unpleasantly of waste oil products. Can this miracle of the bike industry be made to work? The answer is below.
But first it had to be taken apart. It turned out to be quite a challenge. The pants are connected to the legs through long bolts and springs, the bolts themselves are located inside the leg, at a depth of about 25-30 cm. The car market on the industrial market helped with extension cords and a 5 mm hex head. Only the leg was a few centimeters filled with dirty grease, and it was not so easy to hit the head of the bolt with a hexagon, but it was still possible. Having unscrewed both bolts and pulled out the legs from the pants, we look at the guts of this miracle of engineering thought.
Before cleaning:
After cleaning:
Inside we find: - two springs are rusty. - four plastic plugs for the ends of the springs - two rubber bumpers for bolt heads - a 4 cm rubber bump stop located inside the spring and probably serves to reduce the travel of the fork. (Actually not) THE MOST IMPORTANT DETAIL. - two connecting long bolts - pants - a rawhide piece of foil, plays in the hands like a tin can. - legs - a steel monolithic part capable of rivaling the strength of the Nokia 3310
Video (click to play).
This is not Fox F32 Evo CTD. =)
Putting on gloves to the elbows, we begin to scribble shit from everywhere, from the legs, from the pants, from the springs. They are cleaned exceptionally crappy, a lot of rags are gone. There is even more time. After mechanical cleaning, everything is rinsed with cleaning agents in hot water, wiped and dried. By the way, the coating from the working surface of the legs has been safely erased, which means that once the fork still worked. The surface itself, even without paint, is quite smooth, without roughness and irregularities, not a little passable by "zero" to fill up the irregularities, and give hope for the fork's work in the future.
Let's start assembling. But first, let's "pump" the fork a little, increasing its travel. To do this, take the four-centimeter rubber boss described above, and cut it into three parts, 1.33 centimeters each. Fuck one of them. Insert the other two inside the springs, but not into one, but into each one, one at a time. Thus, when the fork breaks through, no metallic sound will be heard and the fork travel will increase from 60 to 86 mm. This is very, very good.
We assemble the structure, lubricating all parts with normal grease in the process. There should be enough of it, but not too much, so that it does not squeeze out during operation, and it does not collect dirt on itself. We pay attention to the stuffing box-anthers (it is not entirely clear what it actually is), there is a cavity inside them, we fill it generously with grease. After assembly, we wipe off all the external elements, remove excess grease, and see what happened.
The fork honestly fulfills its new 86 mm of travel, and even with a slight progression at the end due to the rather stiff springs. Of course not about any compression, rebound, etc. Needless to say, the work is extremely linear and dull. You won't be able to configure anything either. But let me remind you that this is a fork from a segment in which the components are not required to work at all. So I think the result is satisfactory.
I am waiting for the answer from the owner of the fork, I wonder what the impressions will be.
And finally, I will say a little "wisdom". Expensive and cool components are great, but with proper care and maintenance, even the simplest pieces of iron can often be brought into working order so that they can efficiently perform their tasks. Even on Auchan, the forks can work the brakes, brake and switch the switches. Especially if there is no possibility / desire to buy forks for 50k, brakes for 20k, switches for 10k.
A bicycle fork serves more than just a link between the frame and the front wheel. On MTB models, it also serves as the main shock absorber, smoothing vibrations, stress on the arms and negative effects on the mechanisms and the frame. Like any mechanism, it requires periodic maintenance, adjustment and replacement of component parts. And all this will require removal and disassembly. Is it possible to disassemble the bike fork by yourself? Quite, it only takes a little time, a few simple tools and accuracy.
Obviously, there is no need to simply dismantle it from the bike. There are a number of reasons for this - replacement, overhaul and service. Replacement means removing an unusable part and installing a new one instead.
Repair - partial replacement of components. These can be bearings, washers, spring, damper or oil seal. Service includes adjustment, cleaning, lubrication.
The main symptoms that indicate removing the fork from the bike and tidying it up are:
knocking on the go;
the fork is stuck and not adjustable;
bearing wear;
lack of lubrication (creaks);
cranking, heavy steering;
cracks in the legs and pants.
The device of the classic front shock absorption system is a metal spring and a rubber damper. Shrinkage of the spring and elongation of the elastomer rod degrade the properties of the shock absorber, making it stiffer. Regardless of the setting, the fork will knock on obstacles.
Backlash and tight handlebar travel indicate worn bearings and o-rings, as well as a dirty fork cavity. A suspicious creak when the bike is moving indicates that it is necessary to lubricate the part, and you cannot do without removing it.
Any mechanical damage leads to unexpected breakdown of the system. If cracks are found on the body and legs, the fork should be replaced immediately with a new one!
In disassembling the shock absorber with your own hands, you will need tools:
Screwdriver Set;
flat sharp object;
wrenches + sliding;
hexagon;
small hammer.
When working, you will need to clean and lubricate the part again, so you will need a can of grease, a few soft rags and gloves.
And a few recommendations in the end:
check the bike fork for integrity every 500 - 1000 km;
clean the feet on the oil seals every 150 - 200 km of the track;
apply a little grease to the stuffing box of the legs several times a season;
specially for hydraulic shock absorbers - change the oil every 5000 km.
The first step is to get rid of the front wheel. To do this, turn the bike upside down. Release rim brakes by swinging out the clamping bow. With the discs, you can immediately start removing the wheel. Wings and other devices are immediately removed.
We put the bike in the usual position. Now you need to pull out the steering wheel and remove the plug from the glass:
1. Release the side bolts on the stem.
2. Completely unscrew the steering pin fasteners, or "anchor" bolt.
3. The steering wheel is carefully removed from the fork. You can immediately wipe the pipe with a soft cloth.
4. Use a thin sharp object (screwdriver or office knife) to pry the retaining metal washer over the glass.
Use the same tool to press out the gasket under the washer. As soon as the ring comes off the edge of the glass, gently pull it out with your hands.
5. Raise the frame and gently pull the fork out from below. Why? In order not to damage or loose the bearings.
6. Next, you need to separate the crown from the stem.To do this, it is necessary to knock out the connecting ring on which the steering column bearing rests.
Carefully use a thin sharp object and a hammer to separate the ring from the edge of the fork. This completes the removal process.
First, inspect the bearing ring. There should be no damage or broken edges on it. Otherwise, you will need to replace it (if an old plug is installed). Assembly sequence:
1. Put the ring on the joint of the fork with the steering column.
2. Grasp it with an adjustable wrench from above.
3. Using a hammer, press in the ring evenly with soft blows on the jaws of the wrench. We hammer "by sound": while he is deaf, we continue to press, sonorous - the ring has fallen into place.
4. Lubricate the surface of the stopper (grease - lithol-24, buksol or a special compound).
5. Carefully lay the bearing with the balls facing up. You can also put some lubricant on it. A sealing washer must be placed under the bearing.
6. Carefully insert the stem into the glass and repeat all removal operations in reverse order.
You don't need to disassemble the part to replace it, but its repair will require you to "fit" into the mechanism and delve into it thoroughly. Let's consider how to sort out a spring-elastomer type suspension fork:
Unscrew the bottom fasteners with a hex wrench.
Remove the spring compression adjustment bolt - Preload. It is the main damper travel regulator.
Remove the elastomer restrictor or damper.
Take off the "pants".
Using a screwdriver, remove the seals from the pants.
The main reasons why the fork squeaks, makes knocks and does not smooth out vibrations while the bike is moving include wear of parts, water and dirt ingress, lack of internal lubrication. We put in order:
Remove all dirt from the inside of the pants.
Wipe the fork legs, spring and seals thoroughly.
Replace the defective part if necessary.
Install the elastomeric damper (fill in oil through the nipple for the hydraulic fork).
Lubricate the inner cavity - inject oil from a can.
Install the retaining bolt and Preload.
This is how the bulkhead of a bicycle fork looks like with your own hands. Is it needed for a new part? There is an opinion that a plug that has been sorted out at once will be better tuned and will last longer. Much depends on the quality of the kit, but it will be found out in real riding conditions.
Scheduled repairs are done as needed, bulkhead once a season. And of course, you shouldn't forget about prevention. After each ride, remove dirt from the surface of the oil seals, lubricate, check the fasteners and integrity.
A mountain bike, and indeed almost any modern bicycle today is difficult to imagine without a shock absorption system designed to effectively and affordably increase the handling and ride comfort of this type of transport.
Most often, bicycles are equipped with a front suspension fork, thanks to which it is much easier for cyclists to overcome road bumps, even at high speeds, while the load on the palms and hands during the ride is minimal. By minimizing vibration, a well-matched and aligned fork can help extend the life of other bike components such as the frame and steering bearings.
The service life of the plug itself can be extended several times through proper care and regular maintenance.