|
|
Post by limby2000 on Jan 30, 2016 20:15:52 GMT
On starting to strip down the 3x auto boxes. I've discovered that the left hand of the three plungers on both 998 boxes have really excessive movement, at a guess I would say about 10mm, which is 5 times the recommended. I know one of the boxes had the dreaded 3-4th gear flare. Maybe this was the cause.
|
|
|
|
Post by Stu on Jan 30, 2016 21:30:35 GMT
Hi Terry, I had this on mine when dismantling. I guess it'd be worth checking the servo pistons / spring etc, but if you're overhauling everything anyway ............ Martin might be along soon to give us a proper answer  Sorry I forgot all about replying to your pm. Done now though  |
|
|
|
Post by limby2000 on Jan 30, 2016 22:14:34 GMT
No worries Stu, it does seem that the left hand piston sits further out, perhaps that bands worn more. I will know tomorrow.
|
|
|
|
Post by 69hcode on Jan 31, 2016 17:39:55 GMT
The 92 SPI box I pulled apart was the same way. Not sure of the symptoms though. I just know it was bad.
|
|
|
|
Post by limby2000 on Jan 31, 2016 19:20:28 GMT
 may well encroach churchill copyright but could,nt wait to buy one. |
|
|
|
Post by limby2000 on Jan 31, 2016 19:40:07 GMT
After striping down the 2x 998,s the wide brake band was showing serious degrading, the other 2 bands seemed to have left lines on the drums, or is this normal. I can seen the main issue when rebuilding is going to be locating the copper oil feed pipes and the " c " shaped kickdown rod. Very fiddly. I can see why most people get mra to do the rebuilds.
|
|
|
|
Post by mra-minis on Mar 13, 2016 0:47:32 GMT
After striping down the 2x 998,s the wide brake band was showing serious degrading, the other 2 bands seemed to have left lines on the drums, or is this normal. I can seen the main issue when rebuilding is going to be locating the copper oil feed pipes and the " c " shaped kickdown rod. Very fiddly. I can see why most people get mra to do the rebuilds. Hi Terry, It is normal wear and abuse..... it is why my cores are fairly expensive, I did toy with the idea of plasma spray welding to build them up and then cylindrical regrind them to size. The wear is thought to be caused by low pressure, low pressure caused by leaky actuator seals or other leaks, that cause the working pressure to be lower than required and hence slippage occurs resulting in this wear. The bands are normally heavily worn at the ends, look at the friction material thickness, it will thin out at the ends. 3 to 4 flare is caused by the up-change not occurring quick enough, one reason is incorrect oil grade, another is worn seals allowing pressure to bleed off and the third is damaged friction surfaces. I have a tool for aligning the pipes, however I just strip the AP2 off the engine and that way it is easy to fit the later pipes and control mechanism. www.ebay.co.uk/itm/322007730061?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649  Here is my first batch, ready for sale at £24 plus shipping.. |
|
|
|
Post by richard1 on Mar 15, 2016 0:16:37 GMT
Good point, and why I'm adamant in saying look for JASO MA2 motorcycle oil.
|
|
|
|
Post by mra-minis on Mar 22, 2016 22:51:43 GMT
Please note until I can purchase the MRA-Minis URL I can be contacted on martin@kmprecisionengineering.com
just recently I been seeing more damaged servo piston assemblies, ie broken springs, loose or broken bolts.
but excessive slackness in the bands is caused by 2 things
1) worn or damaged band/s
2) worn or damaged clutch body
the slack is measured when the bands are resting on the case supports, never attempt to adjust the movement to take out the distance between the band off and on positions.
In other words the band must NOT be lifted off it's seats unless being operated by the servo piston
|
|
