Originally Posted by JPN

Timing Belt ReplacementTIPS for Volvo 850

My Car: 1994 850 Turbo T5 Sedan, Auto-Gearbox.
My Servicing Interval Preference:
1-Belt only for 60,000 miles/5 years (Volvo recommends every 70,000 miles)
2-Belt, Idler Pulley, Tensioner Pulley, Hydraulic Tensioner & Water Pump for every other belt change.

This write-up concentrates on replacing all parts mentioned above (applies to every other servicing). Please refer to maintenance manuals/instructions for general procedures, I will onlywrite things that require utmost attention that may/may not have been covered anywhere.

REQUIRED PARTS:
1. Timing Belt (Continental Tech, German)*
2. Idler Pulley (Continental Tech, German)*
3. Tensioner Pulley (Continental Tech, German)*
4. Hydraulic Tensioner (Febi/Aisin, German)
5. Water Pump, Gasket & New Bolts (Volvo Swedish or Hepu German)
6. High-Quality Coolant (50/50) (I used Prestone)
*Items 1~3 are available in one package of kit.

REQUIRED TOOLS & SUPPLIES:
1. Various sizes of socket tools, including Torx sockets & universal joint
2. 1/2" drive breaker bar & 12" or longer extension
3. 2-3 sizes of Vise-grip/locking plier
4. 1/2" to 3/4" adapter
5. Torque wrench
6. Engine degreaser (if timing belt/crank pulleyarea is oily)
7. Good lighting (bright LED type is recommended, hands-free type is preferred)
8. Correction fluid/white-out
9. Floor jack & jack stands & wheel chocks
10. Creeper
11. Service manual (I used Haynes) & instructions from:
http://www.volvospeed.com/Repair/timingbelt.htm

Before beginning the procedure, be sure to read & understand the procedure in manuals/on-line instructions. Lift the front-end and rest the car on jackstands, shake it to make sure it's secure. Remove pax-side wheel (loosen the lug bolts before lifting) and fold plastic liner & lock it there with a vise-grip.

Remove serpentine accessory belt by relaxing the tensioner pulley by a breaker bar & 3/4" adapter, it may slip but you'll get the hang of it. At full-relaxed position, insert an Allen wrench/drill bit. Take the belt off.

Following manuals/instructions, align the timing marks on camshafts & crank pulley at cyl-#1 TDC and remove all components that need to be replaced. Enhance the timing marks with correction fluid, but DO NOT mark your own. The crank pulley actually has a big timing botch closer to the pulley, which nobody mentioned. If you can't find it, enhance the existing mark with correction fluid.

TIP-1: TENSIONER PULLEY TORX BOLT DOESN'T COME OFF!
Here's what I did & some alternatives. The access is limited, and the Torx is extremely tight. I ended up stripping the Torx and felt despair. I tried a chisel & hammer belting method but to no avail. I finally took out a 10WR Vise-grip and grabbed the flange around the Torx, turned it CCW. This broke the initial torque and the rest turned like nothing. If this method fails, you may have to drill a hole in the fender and drill-out the Torx. Before resorting to these steps, make sure that you have perfect fit onto the Torx, do the best not to strip it.

TIP-2: THE BELT DOESN'T GO BEYOND THE CRANK PULLEY!
The instructions I used noted that this could be done with the pulley in place. If you have an access to impact tools, you can remove the pulley off, but I had to do it with the pulley in place. It takes a bit of trial, and the belt may have to be bent/crimped in order to get it past the pulley. This shouldn't weaken the belt, unless you really abuse it.

TIP-3: WHAT TO DO WITH THE HYDRAULIC TENSIONER!?
If this item is to be re-used, it has to be compressed by a 7" bench vise and has to be locked with a drill bit (Allen key will be bent). (A new tensioner should come with lock pin already in place). Compress this VERY SLOWLY,spend 10 minutes to do this, or you will damage the seal. When the holeon thepiston and the body align, insert a drill bit to lock it. Install the tensioner on the engine block, noting the correct facing direction and tighten bolts to the specified torque. When everything is in place, remove the drill bit with a Vise-grip and yank it out FAST! If you try it slow, the drill bit will get jammed and you'll have to force it out with a Vise-grip. After the tensioner is in place and the lock pin removed,rotate the crankshaft with a breaker bar for 5 times (or more if you like) to make sure that the valves are not hitting the pistons. Also, make sure that alltiming marks align. There is a white plastic spacer that goes between the tensioner & the tensionerpulley, this can be snapped in place after the tensioner is in place.

When doing the water pump, the pump cannot be lifted up, it has to be dropped down (as far as I know). Clean the pump-mating surface with brass scraper/scotch brite, taking care not to score the mating surface. I used an inspection mirror to get to hard-to-reach areas. Once clean, I put water pumpsealant as well as the gasket on the mating surfaces to ensure leak-free installation. The new bolts came with pre-applied thread sealant, but I put additional sealant.

After the work is done, the engine has to re-learn idle. Turn off ALL electrical devices, even a parking light could screw up the idle if turned on. Let the engine idle for approx 10 minutes.

The access for above procedure is extremely limited, so allow enough time to do this, and do not try to hurry. Again, read the manuals/instructions a few times to get the picture before proceeding. Do not allow oil, grease or coolant onto the timing belt as it weakens the belt.

I wish you luck with your timing belt replacement. Remember that safety is the priority.


JPN