Crank shaft pulley & bolt Removal MX5 1.8 Sport 2002

Hi 

Trying to do a cam belt & water pump change on my 02 reg  1.8 sport. all very rusty. Really not a nice job.

all ready have taken the auxiliary drive belts off and the engine mount so i could access the starter motor bolt (why was this ever put on this way round!)and managed to sheer off 4 bolts even with copious amounts of penetrating oil left on for over 24hours.

 

But it seems that my big problem is the Crankshaft pulley and Bolt.

The 4 small bolts do not want to move at all, I am sure if i put any more force on them they will sheer as this is my experience with this car.

I dont really want to sheer them off.

On the main 21mm bolt I used a 3’ breaking bar with the engine in gear and foot on the breaks but the bolt will not move it just wants to start to round.

I think the main problem is the amount of corrosion on the on the pulley and around this area

 

If anyone has any ideas I would greatly appreciate it as it is looking like my 5 is well and truly grounded for a while.

A bit of cunning and brute force is required, this technique is relevant if you are going to replace the bolts (and pulley) with nice new ones (very strongly recommended).

Break out the plumbing blow torch and the small club hammer.  Heat up the crank bolt until it is thinking about becoming a bit red and then quickly give it a couple of big clean whacks straight on the end with the club hammer (NOT at an angle).  In my experience with other engines the bolt often is only finger tight while cooling down again.  The first time I did this was in 1972 on an old 3.8 Mk2 Jag engine where the bolt was done up to 105ft/lbs and then rusted in to the ‘torsional vibration damper’ pulley and we were bending a six foot extension on the socket, but after the hot whack it undid easily with a ring spanner.

I would leave those little bolts in there.

Get a lenght of scaffolding pole to get the big nut off and then put the whole pully in plusgas or get some heat on it off the car.

You must be using a 12 point or bihex socket. Get a hex or six sided socket as the 12 point is not up to that job.

http://www.ebay.co.uk/itm/1-2-Dr-Deep-Impact-Socket-21MM-Metric-Single-New-By-Bergen-1333-/151951721408?hash=item23610743c0:g:2m0AAOSw~FNUZLXn

I would be tempted to buy a 3/4" drive 6 sided 21mm socket and get a loan of a long 3/4" breaker bar say 6 foot long.

Why have you taken the starter off to do the cambelt, that is not needed.

I did a 2000 Mk2 last year and it was no problem with a bit of scaffold pole.

Hi Drumtochty

 

Thanks for your comments

I have not taken the starter motor off, just moved it so the belt would come off was a much bigger job than i would have expected I needed to loosen the starter motor bolt so i could slide the motor in to get the belt off, the bolt is on the rear of the starter motor and I couldn’t get any movement without taking the engine mount off behind and getting at it that way. I am sure it has not been moved for 8 years but the last time it was done by Mazda.

 

I have got a 3 foot long 1/2" breaker bar but yes it was a 12 pointed so will try again with a 6 sided, it does not look like it is rounded just jumped over the flats.

 

Thanks

Windy gun hex socket done the trick for me.

I think you’re referring to the alternator not the starter motor…

Correct Robbie, I know its the alternator but for some reason put starter motor… and in a previous post too…

Thought that in the last message re alternator.

Yes a good windy gun will do the crank bolt but both my battery operated units and one pretends to do 450NM would not do it.

Hi 

Thanks for the advice.

I have managed to remove the bolt & pulley today. it took the use of a 3’ long breaker bar with a 21mm Hex socket and an air impact wrench with the car in 6th gear and a foot on the brake, it finally came free. 

Great sorted.

This is a major service job you are doing, and you need to invest in a proper crank locking tool or at least loan one from the club as they have a loan out scheme for the rebuild, dead easy, no dead engine, no bigger bills or scrapped roadster, i have seen so many roadsters over god knows how many years from 89 to 05 with crank shaft wear after owners have cut corners, been tight and not done this job correct, DO NOT think that slamming her in gear with your foot on the brake will be great for rebuild, it is not.

Do it right and enjoy her for a hell of a lot longer than cutting corners,It does not pay in the long run, if your local to me i’ll lend you one for the job.

 

I’ll lend you one of these… 

http://www.mazdamenders.net/forum/viewtopic.php?f=193&t=4016

 

M-m

 

I totally agree and was going down the route of locking the crank with a tool… but as I could not separate the pulley from the crank as it was so rusted and the 4 bolts would not move I could not see anyway of removing the pulley so i could attach a tool which i am sure would have made life so much easier.

That was part of my original question. I have had so many bolts just shear on this 5 even after lots of penetrating fluid that I could see the same thing happening with the four bolts holding the pulley on as they did not want to move. so I don’t think the would have worked in this case.

 

 

There are a number of different types of locking tools on the market, the 10mm bolts would of come off the crank pulley to use the clubs tool to lock up which we have also.

But understand your concern with the engine cover bolts snapping…they all do in the end if not protected with grease.

I personally don’t use the board to often so missed your original cry for help, otherwise we would of got you sorted.

M-m