Gen 1. Timing Belt And Water Pump Repair

IS400 · July 22, 2008

Dec 13 2007, 04:43 PM Post #1

Club Member

Group: Regular Member

Posts: 87

Joined: 13-November 07

From: Michigan

Member No.: 57,639

Car Model:Big one

Location:Earth

Warn: (0%)

I just finished a major repair job on my 1990 LS400. Took 3 days of wrenching and two days in between resting.

As a 120lb girl working by herself, I don't think I did too bad. The results are amazing.

1. Got Timingbelt/waterpump kit from CA via E-bay. All Japanese parts and lots of extra stuff like s.plug seals etc. ($200).

2. Lower ball joints and tie rod ends for the front. Wish I had not done them, the old ones were pristine and were tight, but once that pickel fork cuts the seals, not much you can do but replace them. Got the parts off e-bay as suggested by a site member here and it was a nightmare. Three attempts and I still had to settle for a mismatched set of tie rod ends. ($120 for all four parts + my own grease and tie wrap to make the driver's side tie rod work until I can get a spec part to replace it.) Watch out for Miami suppliers.

3. Upper control arms (pair) from Arnott Industries. Beautiful pieces. My god they are sweet looking. ($199 pair) Drop the spindle to the floor using a jack and the spring gets out of the way to unbolt the old ones and put in the new. Jack it back up in place to re attach the strut and you are done.

4. Replaced the PS control valve as a cross referenced tercel part and cleaned out the screen of the servo by the rack again. ($80 + fluid)

5. Two bags of cotton rags to sop up all the oil and fluids that seeped by the drivers side valve cover where the last mechanic from lexus failed to tighten either the bolt on the valve cover at the corner or the distributor housing at the bottom corner. (That is where I had been losing a quart of oil an year and could not find the cause.)

The timing belt had been slinging it everywhere! Used nearly a whole can of degreaser just cleaning plastic covers and crevices around the timing system and crank!

Analysis: The engine had been serviced by someone regularly. That someone, probably a mechanic and not the owner, did not seem to think of failing to torque things that are designed to keep fluids and dirt from migrating into the engine.

My distributor housing, with the cam sensors (look like little silver coins) were covered with a 1/16th of an inch of crud. All from the housings not being tightened or gaskets jammed on and showing gaps and warped edges. Lots of places for things to invade the timing belt cavity all day long in what ever weather or debris the car encountered.

The radiator had pounds of stuff between the condensor and radiator. Surprised the car cooled itself at all.

The throttle linkage had about 1/2 inch of play before the pedal moved the throttle plate. Adjusted and now the car takes off smartly from a stop. Speaking of which, the car is SMOOTH running again. That timing belt had stretched a lot. The new one is much thicker in construction and looks like it is either a factory redesign or the maintenance on my car had been fudged. The timing belt looked old and had cracks everywhere. One crack was 9/10ths the way across the non toothed face of the belt and when I twisted it I heard fibres breaking. I was probably a few weeks away from being stranded.

The seal around the thermostat was torn and needed to be replaced. It looked like the person that installed it was in a hurry and just jammed it on and threw it in there no matter how it was oriented. The steam hole with the little pebble sized flapper was not pointing straight up like it should either. Replaced both pieces along with the o-ring for the housing ($40) at the local Lexus Dealer. Ouch! Glad I was not forced to buy the other parts there!

The car runs smooth now and does not clank or bang over expansion joints or irregularities. Now though, those rear carrier bushings are obvious and the next thing on my list.

BTW the best method I found to keep the engine from turning while removing the harmonic balancer when doing the timing belt, is quite simple and a tool we all have at home.

Get under the car, look for the access panel where the trans meets the engine and take off the two bolts and look for the round holes (big) in the flywheel. Take the largest Allen Wrench you have (90 degree style with a short and a long end, not the T handle ones) and slip the short end of the wrench inside one of the large openings. Slowly turn the engine over with your breaker bar and you will feel sudden resistance in about a quarter turn or less. Now you can take off that 180 foot pound bolt with no problem. I had to get on the fender and use my legs since i am a girl, but it is the perfect tool to make it a one person job.

Just remember to take it out before you start your engine! Eeek!

Alert: My 1990 did not have obvious timing marks for the cams. I marked the cams with a sharpie and eyeballed a fixed point behind them on the sparkplug wire holder. Kind of like dead reckoning in the woods. See a tree on the heading, go to that tree, pick another tree on your heading, etc...

Well I had set everything and had marked the crank and taken off the belt and was about to go to lunch and thought I really can't see any marks to interpret on the cam gears, so i made my dead reckoning marks and ran the new belt around to see how the stiff new one was going to be getting in place and --whizz, the passenger side cam gear rotated on its own about a 1/3 of a turn in a split second.

My heart jumped and I thought oh no, I lost my timing! I took a look and turned the gear back to the mark and realized it was under compression or at the top of its stroke or something. I felt a good amount of resistance until I got it back on mark and it rested there and did not move again. I have a feeling if I had not made that mark I would have had to guess or at least not felt confident I had done the job right when I turned the key to start it up the first time.

Mark your stuff as soon as you get the crank at top dead center. Do not mess around with knowing where you started from because weird things can happen when you least expect it.

Last FYI. The tutorials do not list the huge bolt running perpendicular in plane to all the other bolts. It runs through the housing under the ac compressor and needs to be removed to take out the water pump. When your engine is covered in crude you cannot see the seams where the metal meets. Look at your new part and use it as a guide. When you remove the old pump don't use a chisel like the tutorial says, there is a tab on the pump in the passenger side quadrant that lexus designed into the part to make it easy to pry off. I just used that same allen wrench like I would open a beer bottle. A flick of the wrist and the seal is broken and you can pull the old pump off a little at a time until it slides free.

Happy Holidays everyone!

Update: I just posted this in July 2008 after some of the members recommended it would be a good tutorial. Make sure to follow all the recommened precautions your tools list and take your time! Ask questions on the board if you are stuck or not sure. A torn down engine with a screw up is not what you want to have flat bedded to lexus when you make a catastrophic mistake. Good luck and get ready for in incredible feeling of satisfaction when you get it done!