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All you need to know about the M90

Being the fool that I am, I took the gearbox apart and forgot to reinstall the above mentioned ball, spring and bolt. Then again being as smart as I am, I somehow suddenly remember JW talking about it in this thread and my problem is solved :hyper:

Since I already bought a parts car I now have a spare M90 :-)

NICE! Good to hear that it was a simple fix! :)
 
I'm about to reinstall mine. I have a new set of seals/gaskets for it. Just wondering if there are any special tools or methods needed to get them installed.
 
Nope

I didn't have to use any special tools or technics to install the new seals.
I put on my other gearbox today because my underdrive pulley is broken and I took out the gearbox to be able to get it off. I think the one with the new seals was leaking.
 
M90 release fork vs. M47 release fork

Would someone please explain differences between M90 and M47 hydraulic clutch release forks.

I have fork that came with M90 but I have reasons to doubt it is M47 and since you cannot stress enough that only M90 fork must be used, I would need some explanation.
And don't only tell difference is in hole because it could have been made by fitter in order to make the slave cyl adjustable.
1007928.jpg
1007927.jpg
 
I've only ever seen the plastic ball cup on an M90 fork, but that's not definitive...and those pics appear to show the plastic cup on what I assume are both types.

We ran an M46 fork for a while by accident. It worked, but the pedal was horribly heavy.

cheers

James
 
What's the code for seal where gear selector goes into M90? Seems same size as M46 but cannot be found on any Vadis drawing.
 
I just finished my install into 245.
I had 2 forks, one with hole and another without. And this was their only difference. Length, brearing mating, pivoting place: all same. They can differ only in pivoting as M90 should have that plastic bushing. Can that bring horrible clutching that people have reported before? IMHO not, unless there is third hyraulic fork type. I used the one with hole and made slave cyl adjustable with threaded bar and nyloc nut.

I went for the M47 modified mount as most usual here in TB and here, although I would have liked the capt. Bondo style. Then again now - after seeing I how steady the setup with M90 gearbox mount is - I am happy. M46 moved and rotated much more with its originial rubber mount. It seemed reasonable to lower the gearbox more than others have done here and I used aluminium spacers found on AW70. With that height it seems that two pieces of propshaft are coincident.

Propshaft came from 940 M47 with its original center support. I will have to take this picture to show my setup there but basically welded 940 support with its piece of sheetmetal to 200 bracket. And bracket is in original 200 place..

Tunnel got quite a lot of smacking. Sadly the place where it needed it most - upper left side of gearbox, where a bolt protrudes - was too strong for our hammer. It has about 5mm on spacing now but as gearbox is almost not moving at all, so it seems OK.

Pedals. The distance between original, cable and new, master cylinder fixing is 10mm. It came as surprise that I needed to mount pedal to higer, luckily existing holes. I didn't like the idea of removing the whole pedal box and manged to take the clutch axle bolt out and put into new place while all the rack was in the car. Needed quite a lot of luck and patience but it was the only way for me as I hate dismantling things that are not directly under work. Clutch pedal is now some 7cm higher as the new placement came as surprise and we didn't have MIG at hand. Lets see if i get used to that.
Also you need different spring. Original hydraulic looks like this but as this came as surprise we modifid original: reversed it to be pushing upward and bent the ends when red hot.

Its fun to do this kind of tuning on volvos because so many things fit between generations of cars. I used 200 gear stick because I like it more. All bushigs below and in the midde are the same. Its good idea to remove the rear gear slider "button" so that muscle memory woudn't use 1st gear instead of rear.
Then again I feel sorry for volvo engineers who were not allowed to change 20-30-40 year old designs.

My clutch: Sachs 940 TD pressure plate + new NK disk that got new Ferodo linings that were told to be better biting. We'll see about that. M90 thrust bearing. Its mating area is different than M47 bearing but again: side by side to M47 bearing/fork did not show difference in height. My hands were too dirty to handle camera. Anybody can confirm that?

Replaced all seals and oil but the info about the gear selector seal came too late.
Also 3rd gear was left original. Lets see if it breaks.
All new cyl's boots.

Also flexible hose is yet to added to clutch hydraulics.

I am surprised how loud it clicks when changing beween gears. Is it my imagination that it should click less than M46?

But basically it seems to be success and lots of building fun.
 
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the stock shifter gave very slick shift without any noticeable clicks
since i installed the avalange short throw speedshifter it is more of a clicking action. Still smooth though
 
Ayee I used my old short shifter from M46 which is some 1cm lengthened.

Did anyone start the engine when M90 installed but propshaft not? 1 and 2 were quiet, in third you can hear some and 4 made quite loud rattle. I take its normal domino effect of gears when they have no load.

Today had a longer testdrive. Damn. Something's grinding.
 
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I'm using an M90 in my kit car. I'm using a non volvo m/c and I'm having trouble getting the clutch to work properly. Basically I have to have my foot right to the floor and then I can just about change gear, but it's hard. As i know flip all about hydraulic clutches, could this be a problem with the m/c not being big enough or a problem with the slave cylinder? It's a 3/4" m/c, I don't know what the m/c that came with the 960 was. There's no leaking fluid anywhere. I'm using an 850 clutch & flywheel. This is the kind of m/c i'm using, the .75 one

Any ideas on what I can do. FANX

is the master cyl. adjustable if so start with that before ya go adding shims
 
John did a small run - 3 pieces i think - of M90 short throw shifters. I just installed and tried it, and damn I like it. It has nothing to do with the M46 the car once came out of the factory with. It kind of reminds me of an MX5 i once drove. Clean, crisp, short throws. It does require some more force to shift gear compared to the original M90 shifter, but it's worth the extra effort.
 
is the master cyl. adjustable if so start with that before ya go adding shims

Absolutely right. The clevis on the master is adjustable, and will most likely need to be adjusted.

This threads remonds me I need to hit up John about a short shifter, or even just the bushings.
 
Did some thinking. (Ouch... that hurt )

Why not use an 850r clutch disc and pressure plate (240mm) and the stock dogdish (m4*) flywheel, machine flatten the dogdish flywheel and drill & tap 6 holes for the m8 screws? Then you have the dogdish with the 60-2 pattern for LH and a 850r clutch setup (240mm) for more clamping pressure? Do I need to make any modifications on the clutch fork ? Any thoughts about the height of the setup?
 
I wouldn't spend my money on having someone machining the stock flywheel, waste of money imho, and the result is to risky I think.

The TTV billet flywheel I have in the 760 is unbeatable in price/quality. I bet you that adapting the volvo dogdish is already pretty expensive and time consuming anyway.
 
I wouldn't spend my money on having someone machining the stock flywheel, waste of money imho, and the result is to risky I think.

The TTV billet flywheel I have in the 760 is unbeatable in price/quality. I bet you that adapting the volvo dogdish is already pretty expensive and time consuming anyway.

OK, did a little searching:

B230 Red Block 850R 'Lite'

Lightweight billet steel
Single piece design integral teeth
Suits standard 850R diameter clutch
Dynamically balanced
Weight: XXKg
Part number: 1090

Stockist: info@ttvracing.com


Is this the one you have?
 
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