1990 Coupe crank sensor replacement question...

[ptt]

I am about to tackle the crank position sensor on my 90 coupe.  I have replaced the harmonic balancer on my 90 convertible a year ago when it started chattering.  Unfortunately I can only find my 1988 FSM and it doesn't refer to the bracket that shields the sensor.  It appears to support the little damper shock on that side of the engine.  I don't recall there being any issue with removing this bracket to get the HB off of the 90 convertible.  Will there be a bolt alignment issue when putting the bracket back onto the block (two bolts)?  Also, as I recall I used an electric impact gun to get the crankshaft bolt out.  I hope that's OK.....  Thanks.

Edited June 22, 2017 by ptt (see edit history)

[2seater]

There should be no issues with alignment for reassembly. There is no direct connection between the engine and the frame bracket except for the little shock absorber, which is a flexible item. The impact should work fine and as a matter of fact, I use an impact to remove the nut from the bottom of the shock absorber too, so I don't need to try to hold the shaft. 

[drtidmore]

In the past few years I have had to replace the harmonic balancer twice on my reatta and in neither case would my electric impact wrench budge the bolt.  What I did both times was, with the car on jack stands, using my long breaker bar angled down such that it hit the ground forward of the engine, with the ICM disconnected, I would bump the starter and bingo, the bolt released.  I know it sounds scary and certainly you do NOT want to be near the area just in case the breaker bar snaps, but this trick has been used by quite a few.  I suspect that a pneumatic impact wrench might well break loose the HB bolt. 

[89RedDarkGrey]

4 hours ago, drtidmore said:

What I did both times was, with the car on jack stands, using my long breaker bar angled down such that it hit the ground forward of the engine, with the ICM disconnected, I would bump the starter and bingo, the bolt released.

 

Yes.

 

[ptt]

My crankbolt isn't 18mm...its apparently 23mm.  I also noted my 23mm impact socket has disappeared so I have to go buy a replacement.  I did notice that when I pulled the electrical plug from the sensor that there was lots of oil present IN the sensor.  No wonder it failed.    

On ‎6‎/‎22‎/‎2017 at 1:13 PM, 89RedDarkGrey said:

 

Yes.

 

 

[89RedDarkGrey]

5 hours ago, ptt said:

My crankbolt isn't 18mm...its apparently 23mm.

 

It was 18mm OEM on my '89, and the new HB came with a new crank bolt- which is 23mm. Is your '90 HB OEM? Maybe another run change in production?

 

If you should need any guidance- this is an excellent video-

 

 

[2seater]

On ‎7‎/‎4‎/‎2017 at 5:20 AM, 89RedDarkGrey said:

 

It was 18mm OEM on my '89, and the new HB came with a new crank bolt- which is 23mm. Is your '90 HB OEM? Maybe another run change in production?

 

If you should need any guidance- this is an excellent video-

 

 

When I was looking at the various engines Daves89 had to select from we did discover two different crank bolts, I don't remember the head size, but one style is necked down between the head and the threads and the other is full width the entire length. I know the three bolts I have are full diameter with a 15/16" head. They came from '89 and '90 engines. The necked down one, with the possibly smaller head, MAY have come from the '88 engine?

[89RedDarkGrey]

This is my OEM '89

 

[2seater]

1 hour ago, 89RedDarkGrey said:

This is my OEM '89

 

Well, then they are at least three different bolts, large and small head full diameter and a reduced diameter bolt, hex size unknown?

[89RedDarkGrey]

5 hours ago, 2seater said:

hex size unknown?

 

[2seater]

I just meant I saw the reduced shank bolt but not the wrench size required.

[DAVES89]

I took some pictures of the Hamonic balancer bolts we removed from the engines I acquired doing the engine swap on the Red. I sent them to Ronnie so they should be posted soon. 

 The tapered one that 2seater refers to is from the 1988 Buick Lesabre engine. It has aproximately a 28 or 29 mm head [I don't have either size socket but have a 27 and 30] or the American equivilent.

 The other bolt is the usual Reatta bolt, 24mm in size but this one is off a 1990 Buick LeSabre.

[Ronnie]

These a Dave's photos.

 

 

[Ronnie]

On 7/4/2017 at 6:20 AM, 89RedDarkGrey said:

If you should need any guidance- this is an excellent video-

 

It is a good video but I take issue with him saying a puller is needed because the balancer is a press fit. I have only changed 2 balancers on a 3800. One on my Reatta and one on my neighbors 1989 Oldsmobile with a 3800. Both of them pulled right off by hand after removing the bolt. I thought the '91 Reatta was the only one that press fit.

[89RedDarkGrey]

I know my '89 didn't come off quickly or quietly- it took several hours of levering, beating, and swearing. Maybe it depends on environmental factors.The '89 OEM has no holes for a puller, because like you stated- it shouldn't need one.

 

 

All of the "Aftermarket" brands of RockAuto do have the 3 threaded holes, regardless of year.

[drtidmore]

Having recently replaced my Reatta's HB (failed due to backfire) and this being the 2nd one in the last few years (1st was to replace the factory install), I can state that the HBs sold for the 89 Reatta at Autozone do NOT have the 3 bolt holes for a puller but I had NO issues with pulling either off the crank once the bolt was removed (simply pulling with both hands was all it took).  It was interesting the GM installed a splash guard on the "sedan" installation of the pre-series1 3800 but not on the Reatta.  I found the OEM crank bolt as well as aftermarket replacement to be 24mm heads.  I used that same method of sensor alignment as the guy detailed.