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Brass linkage bushings and shortening shifts
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dropnosky Offline
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Post: #1
Brass linkage bushings and shortening shifts
Figured Id move these links that Charmalu found into their own thread because they look like excellent ideas! Here are a few teaser pics-
   
   
   
   
   

Quote Charmalu-
"Last night I was Googling for some info on the Getrag 5-spd trans. I came across a web site in the UK.
http://mercedes-190.co.uk/forums/5951

some of them are using brass bushings on the shift linkage to tighten up the shifts, in stead of using the rubber/nylon.
http://mercedes-190.co.uk/topic/217321/1/

there were 2 thread on shortening the shift throw
http://mercedes-190.co.uk/topic/6576914/1/

http://mercedes-190.co.uk/topic/222107/1/

I haven`t seen one yet, but there is a 6 spd Getrag, with 5th 1:1 and 6th OD. they come in the SLK 230 W203, not sure is that model come over to this side of the pond.
http://mercedes-190.co.uk/topic/6568052/1/"
01-18-2010 08:52 AM
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winmutt Offline
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Post: #2
RE: Brass linkage bushings and shortening shifts
I would be interested in a set of longer arms. I need to pull my spare shifter apart in preparation of making a 5 spd shifter.

1987 300D Sturmmachine
1991 300D Nearly Perfect
1985 300D Weekend/Camping/Dog car
1974 L508D Motoroam Monarch "NightMare"
OBK #42
(This post was last modified: 01-19-2010 03:53 PM by winmutt.)
01-19-2010 03:52 PM
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CID Vicious Offline
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Post: #3
RE: Brass linkage bushings and shortening shifts
[Image: normal_PIC_0025~0.JPG]

Bushing for the gear lever.These measure said 18,45 outer,8,3 width and 6mm inner diameter.

[Image: normal_PIC_0024.JPG]
Bushings for the shifter arms at the box.These measure 25mm diameter at the section that goes through the arm.The flange is 30mm outer on 2mm width.
Bushing protrudes 3,5mm into the arm per se and the through hole is 9mm flat for the shifter rod.

[Image: normal_PIC_0023.JPG]
Bushings for the arms at the bottom of the shifter per se-underneath the car.
Dimension are....
Flange dia 25mm
Where it protrudes through the arm=15mm on a 3mm width

Through hole for the shifter rod is again 9mm flat.

-----


Just wanted to get the pertinent info up there. I agree with one of the posters on that forum, get them made at a local machine shop.
(This post was last modified: 01-19-2010 06:31 PM by CID Vicious.)
01-19-2010 06:29 PM
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willbhere4u Offline
do the interns get glocks?
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Post: #4
RE: Brass linkage bushings and shortening shifts
I had to replace the transmission in my 240d because of loose shifter bushings

It accidentally got stuck in 2 gears and stuck 1st gear out of the side of the case I used 2,3,4 gear to get it to my shop even after it leaked all of it's fluid out! It made lots of bad noises except in 4th it worked great

on a side note I have a core 4spd trans slight damage! lol

1987 300SDL soon to be 6spd______6cyl 6spd
1985 300td euro 5spd wagon ______5cyl 5spd
1980 240D 4spd Rajay turbo kit_____4cyl 4spd
1964 220S
(This post was last modified: 01-19-2010 08:21 PM by willbhere4u.)
01-19-2010 08:20 PM
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dropnosky Offline
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Post: #5
RE: Brass linkage bushings and shortening shifts
trying to figure the shift throw out beforehand with a diagram and some rusty geometry/algebra so I know just how much to lengthen the linkage under the shifter as related to degree of swing on the shifter. Someone check my math!

Assuming the stock shift throw degree is “X” and the desired shift throw is “Y”.
Assuming the stock Length above the fixed point (shift handle) is L1 and the length to alter is L2.

We know that the angle of the shift throw is inversely proportional to the length below the pivot. In other words, the shorter the shift knob, the higher the degree below the pivot.

So the equation would look like

L2/X =L1/Y,

For example, if we measure the stock configuration degrees of movement of the stick handle, and we know how much we want to reduce it by which gives us our desired degree of movement, lets say a shift that moves half the distance.

So for fun, if L1 =10”, X = 30 degrees, Y= 15 degrees, then,

L2/30=10/15,

L2= 20” (your total length below the fixed point)

Im not sure Im setting this up properly, and if I really remember how to do equations like this, but we should be able to exactly calculate just how far to modify the linkage under the shifter by the number of degrees we want the shifter to move. I feel like I did something wrong here though, because the relationship is reverse in real life, the shifter handle is longer than the linkage bar directly underneath

   

1974 240D 4-speed
1989 Chevy Astro
1987 VW Quantum wagon 5-speed
(This post was last modified: 02-10-2010 03:55 PM by dropnosky.)
02-10-2010 12:22 PM
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Oil Burner Offline
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Post: #6
RE: Brass linkage bushings and shortening shifts
Has anyone tried to cut off the Mercedes ends and just tread the rod and install small Heim Joints You can get those at any tractor supply and that would stay true for allot longer and would not bind.

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04-19-2011 09:35 AM
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stan Offline
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Post: #7
RE: Brass linkage bushings and shortening shifts
(02-10-2010 12:22 PM)dropnosky Wrote:  trying to figure the shift throw out beforehand with a diagram and some rusty geometry/algebra so I know just how much to lengthen the linkage under the shifter as related to degree of swing on the shifter. Someone check my math!



not going to check your math but i have an alternate approach.

the levers on the tranny need to move a certain amount, and we can express that as linear motion of the shifter linkage rods. you could calculate the linear travel of the end of the shifter arms using trig, and use this to find how you must modify things.

if your original shifts are thus: to engage gear G, shifter endpoint E must travel linear distance L, as a result of angling the shifter R radians. The stock shifter measures Z inches from shifter pivot point to shifter linkage rod. L is equal to the arc length of circle formed with radius Z. that means (L inches) = (Z inches) x (R radians). you need to maintain the same value for L - meaning your linkages will push that lever on the tranny the same amount, otherwise you could have wonky shifting.

if you want to shorten your shifts, in other words decrease R (the angle the shifter is at when you are in a gear) - you need to increase your Z measurement. if the stock shift levers are 3 inches long and require you to angle the shifter pi/6 radians (~0.52333), and you want to decrease that to pi /12 radians (~0.26167) , then your lever would now need to be ~6 inches long.

this is not a perfect solution but it is the simplest way that comes to my sleepy head, and involves no trial and error - just careful measurements.
04-20-2011 05:19 AM
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Captain America Offline
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Post: #8
RE: Brass linkage bushings and shortening shifts
Get your 3:19am post outta here Stan I Am!

1982 300D Turbo ... The Tank ... E-fans, Exhaust/Down pipe ends at Firewall, A/C delete, ALDA delete, Rack limiter delete
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04-22-2011 01:35 AM
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unaleman Offline
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Post: #9
RE: Brass linkage bushings and shortening shifts
(04-22-2011 01:35 AM)Captain America Wrote:  Get your 3:19am post outta here Stan I Am!

I bought a set of bushings for a 190E 2.6 with clutch from somebody on 190REV only they were made from Delrin I think.. anyway I can say that the two that go in the shifter itself which are the two at the top of the pictures here made a HUGE difference in feel of the shifts not quite snickety snick but WAY better than the rubbery vague feeling from the stock metal and rubber which are usually toast.
04-22-2011 05:56 PM
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