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SR20DET Drive belts and front main seal

DIY: SR20DET Front Main Seal/Drive Belts

Taking off the drive belts on your S13, S14 or S15 SR20DET can serve many purposes. Replacing worn belts, replacing pulleys, replacing front oil seal, removing timing chain front cover/oil pump, whipping naughty children… Ok maybe not the last one.

My aim in removing the drive belts was to actually remove the front cover to inspect my timing chain, that part never eventuated though so I ended up replacing the front oil seal just for the sake of it and making a costly mistake of damaging my crank pulley and front cover. But luckily for you, you won’t encounter those issues with my guide!

Tools required: ratchet/tool set, seal puller, breaker bar, 27mm socket (if you’re going for the front oil seal), 3 jaw pulley puller, picker set
Technical difficulty: Low
Profanity level: Medium-High
Duration:  2 hours to infinity

  1. Remove or move the cold side intercooler piping out of the way (one that goes into the intake plenum). This’ll mean disconnecting the vacuum and BOV line.
  2. Unbolt the 4 x 10mm bolts on the fan itself and manoeuvrer it out through the shroud (takes a bit of wiggling but it’s possible).
  3. Remove the hose going from the radiator into the coolant neck for ease of access for the next step.
  4. Unscrew the shroud from the radiator via the two top screws and wiggle it out. The hotside will be the hardest but being plastic you can bend it and use a bit of force. Don’t go breaking anything though. Or if you wanted to do it properly remove your radiator too.
    SR20DET Drive belts and front main seal
  5. Time to get those belts off! To the untrained eye you’ll just look around and wonder what on earth anything budges to provide slack to get them out. Ahh but those cheeky engineers have a way.
  6. Thinnest belt first which will the one on the Power Steering Pump pulley. Loosen this top bolt which will allow movement.
    SR20DET Drive belts and front main seal

    Then loosen the front lock nut on here which will allow you to unwind this bolt which determines the movement range. You should be able to put some downward pressure on it now which will give the belt some slack to remove it. If not keep unwinding the last bolt.
    SR20DET Drive belts and front main seal
  7. For the middle belt, loosen the front nut and bolt on the tensioner & pulley which will allow this pulley to drop making the belt loose to take out.
    SR20DET Drive belts and front main seal
  8. For the final thicker alternator and water pump/fan belt, loosen this rear nut to allow movement.
    SR20DET Drive belts and front main seal

    Loosen this front nut:
    SR20DET Drive belts and front main seal

    Now once you relief the tension on the adjustment bolt, alternator can be drop slightly allowing you to remove the belt!
    SR20DET Drive belts and front main seal
  9. Now with all the belts off, time to get that front crankshaft pulley off.
  10. You will need a jaw type puller for this, there is no better way.
  11. There’s a bit of fiddling involved here but eventually you will get the claws onto the 3rd ring of the pulley (the metal is thickest there as I found out the hard way). Ensure all the claws are in as much as possible to avoid unnecessary chipping *cough*
    SR20DET Drive belts and front main seal
  12. Wind the puller with your ratchet/breaker and you should start slowly seeing it loosen from the front cover. It will be on extremely tight so be patient and apply strong slow pressure. You should be able to then use a screwdriver or similar to pop it off.
  13. Pull out front main seal with a picker. Work your way around behind it pulling it towards you. It may end up crumbling to pieces but you’ll eventually get there.
    SR20DET Drive belts and front main seal
    SR20DET Drive belts and front main seal
  14. After its off wipe off the bits of rubber and gunk inside.
    SR20DET Drive belts and front main seal
  15. Lub the new seal with oil and pop it in. The closed part of the seal faces the outside. I tapped the seal in gently with a hammer against something flat against the seal. Once it sits flush happy days (it can only go in so far).
    SR20DET Drive belts and front main seal
  16. If you’re not a moron like me you can use your old crankshaft pulley. Give it a good wipe and make sure there’s no dirt/debris in the grooves.
    CHECK!!! MAKE SURE you line it up 100% with the woodruff key (notch on the crankshaft) before putting pressure on it to push it in. You don’t want it misaligned in the slightest (resulting on the key not completely in the pulley hole and pushed on the edge instead) and then forcing it on and subsequently shattering the woodruff key and cracking the front cover (yup that’s what happened to me).
    SR20DET Drive belts and front main seal
  17. It’s a pretty tight fit so once you’re confident it’s on properly it’s time to use the bolt to push it all the way in. Clean the bolt and lube it with some new engine oil first as per FSM recommendation. Thread it in and torque it in, FSM says 112ft/lb so yep put your back into it! Pretty easy to get the click when going from the top.
    SR20DET Drive belts and front main seal
  18. Pop the thickest belt on first and push down on the alternator to allow slack for the belt and tighten the adjustment nut accordingly. When the belt has enough tension (can twist the belt ¼ – ½ without too much force) tighten the 14mm adjustment nut and the bottom rear one to secure the position. Lightly tighten the 12mm front bolt too. Check that the belt is properly seated on the grooves on all pulleys.
  19. AC pulley is pretty simple as you just turn the 14mm adjustment bolt on the idler pulley so that it moves up putting tension on the belt. Tighten the front 14mm nut when you’re happy with the tension.
  20. Last belt! Power steering belt is simple enough too, tighten the 14mm adjustment bolt for it to move up putting tension on the belt. When ready the front 14mm bolt to lock the movement. Again check the belt is secure on the pulley grooves.
  21. Depending on whether you have most of your intake off or not, you may want to bolt on your fan now via the 4 x 10mm bolts. Otherwise you can sneak it in on an angle after putting the shroud.
  22. Getting the fan shroud back in is definitely much easier than taking it out. Easier way is to pull the exhaust side of the shroud in and the rest should drop down. You’ll need to use a bit of force nudging against the AC lines but once that’s clear it’ll drop straight down. Remember to check underneath that it’s sitting inside the placement holes and you bolt it up to the radiator on top.
  23. And put back all of your intake side and that’s about it! Nothing too hard about it 😛
  24. Start the car and check any leaks especially from behind the crank pulley and also squeaky belts. If squeaky then the belts may need some more tension. If leaky oil then either the seal or crank pulley isn’t on properly but lets hope you’re not put into this scenario (like me…).
    SR20DET Drive belts and front main seal

Hopefully getting off that crankshaft pulley didn’t give you any grief and you didn’t have to fork out money for a new one. I had to cough up a new one ($400) and also a new front cover ($300)… and a new woodruff key just because I didn’t line up the crank pulley 100% and forced the bolt in, definitely not fun!

But hey you live and learn, just remember no shortcuts when it comes to your engine.

SR20DET Drive belts and front main seal

About Flop

Open minded car enthusiast who appreciates most things on four wheels although JDM is where his heart lies. Wannabe racecar driver but having trouble fitting into his bucket seat since he's also a dedicated gym goer.

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  1. Awesome write-up with very clear picture. I was able to remove all drive belts on my SR20DET without any problems. Just one question after re-tensioning the new belts, how much torque do you apply to the various locking nuts? (those that lock the tensioner in place not the adjusting bolts)


    • Flop

      Good to hear our guide was useful! As for the torque we’re not entirely sure as we ended up snapping the alternator tensioner bolt :\ Should have looked it up in the FSM…

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