The arm is loose on the body .How do I tighten it?

If you can move the wiper arm by hand, the nut attaching the wiper arm to the pivot is loose. There is usually a plastic cover over the nut. Lift the plastic cover up to expose the nut and retighten it

the wiper arm may have come loose from the motor linkage , where the arm joins the linkage outside of bonnet/hood there is a flip up cap , under there is a nut that holds the wiper arm in position , this may be loose so remove completely then remove the arm as the splines may not be in the correct position, replace the arm so that when it is laid back down on windscreen it is level with the bottom and tighten the nut , you must tighten the nut with the wiper arm raised so as to get a good fit , this may require a couple of attempts to get in the exact position when wiper arm is laid back down, hope that makes sense

It sounds like the blade has come loose on the shaft. The motor is turning the shaft, so you have a fairly easy job of tightening the blade and arm to the shaft. Look at the assembly where the big round bit that drives the arm goes into the body. If it's not missing, remove the round cover, You'll see a nut there. Tighten it up, put the cover back on, and the job's done.

Check where the wiper arm bolts onto the mechanism

Its pretty simple, with the bonnet closed follow the wiper arm (the bit the wiper blades fit onto) down to the body.

Normaly there is a little cosmetic cover that just clips over the bolt (its kinda round)

Lift this cover up, sometimes you might need to wedge it with a screw driver.

Check if the bolt isnt loose if it is just tighten it up if it isnt remove the bolt(turn anti clockwise) put a washer on the shaft and fasten the bolt again.

Hello ggagne.
Here is the procedure.

1. Raise and suitably support the vehicle.
2. Remove the left tire and wheel assembly.
3. Remove the pinch bolt from the lower intermediate steering shaft
4. Loosen all insulator clamp attaching bolts.
5. Place a jack stand under the center of the rear frame cross member.
6. Remove the rear frame-to-body bolts.
7. Lower the rear of the frame just enough to gain access to the stabilizer shaft.
8. Remove the insulator clamp bolts and the clamps from the frame.
9. Remove the insulators from the stabilizer bar.
10. Remove the stabilizer bar links from the control arms.
11. Pull the stabilizer shaft rearward.

Installation

1. Insert the stabilizer shaft to the left side of the vehicle. Important: DO NOT tighten the stabilizer link nut at this time. The weight of the vehicle must be supported by the control arms such that you can obtain the vehicle design trim heights before tightening the link nut.
2. Loosely install the stabilizer shaft link at the control arm.
3. Install the insulators on to the stabilizer bar.
4. Connect the insulator clamps to the frame.
• Tighten the stabilizer shaft bracket bolts to 48 Nm (35 ft. lbs.) .
5. Raise the frame into position while you guide the steering shaft onto the gear.
6. Install the new frame-to-body attaching bolts.
7. Remove the jack stand.
8. Install the pinch bolt and tighten.
9. Install the left tire and wheel assembly.
10. Lower the vehicle.
11. Support the weight of the vehicle by the control arms.
12. Tighten the stabilizer link nut.
• Tighten the stabilizer shaft link nut to 23 Nm (17 ft. lbs.)
  

There you are, I hope your job goes well.
Thank you for using FixYa.

KL

its possible the nut that tightens the wiper arm has come loose. just center the wiper arm in proper position and try to tighten the nut.

No way to tighten What actually has happened is the body is broken loose where the arm attaches. This is a known problem with the 850 and the S/V 70 series volvo until 2001. The only repair is to have it welded.

have you tried tightening the bolt yet? There are no access points that is for sure. If you have tried tightening it and the nut is just spinning you might be able to tac weld it back on with a MIG welder.

The rod that is bad, fell off or the wiper itself is stripped out