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B4 servo

Help, Advice, Owners' Discussion and DIY Tutorials on Volvo's stylish, distinctive "P2" platform cars.

2001 - 2007 V70
2004 - 2007 V70 R
2001 - 2007 XC-70
2001 - 2009 S60
2003 - 2007 S60 R

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vtl
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vtl

Re: B4 servo

Post by vtl » Mon Aug 12, 2019 8:05 am

Katten wrote:
Mon Aug 12, 2019 7:32 am
Is there any way of knowing how much longer the piston needs to be? Or to know if it needs to be longer at all. My piston has two bands running on the top cone.
Yes, you can check the piston travel, and it should be within the specified range 5.76-6.76 mm (mentioned on the second photo I posted).

Unfortunately, it is not really possible to measure the travel with transmission sitting in engine bay, so 0.5mm for every thousand miles is a good guesstimate ;)

I welded more after taking the picture, the pin is 1 mm longer now. But I may try to take one washer out first and see how it goes.


2005 XC70 250k
2016 XC60 40k

Katten
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Re: B4 servo

Post by Katten » Mon Aug 12, 2019 10:07 am

I just got a piston and cover from the junkyard for $5.
Same type as my car, two lines and same length. Might use one of the to weld and experiment :). Does this piston have anything to do with the 3-4 gear change also?



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vtl
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Re: B4 servo

Post by vtl » Mon Aug 12, 2019 10:16 am

Katten wrote:
Mon Aug 12, 2019 10:07 am
Does this piston have anything to do with the 3-4 gear change also?
Yes. The 4th gear is engaged then the 3d is disengaged. When the piston can't move backwards fast enough (because it has to push more ATF in the same amount of time) you'll feel something like short slow down/power loss.


2005 XC70 250k
2016 XC60 40k

Katten
Posts: 19
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Katten

Re: B4 servo

Post by Katten » Mon Aug 12, 2019 10:26 am

vtl wrote:
Mon Aug 12, 2019 10:16 am
Katten wrote:
Mon Aug 12, 2019 10:07 am
Does this piston have anything to do with the 3-4 gear change also?
Yes. The 4th gear is engaged then the 3d is disengaged. When the piston can't move backwards fast enough (because it has to push more ATF in the same amount of time) you'll feel something like short slow down/power loss.
Okay, i might have screwed up abit. When I took out my pison i polished it since it had lots of ware on one side and also the part where the o-ring goes on the piston was jaggered/scoored on a few places. Polished that too. Also took a 2000 grit sandpaper and took out som wear on the cylinder walls where the piston travels. Could feel a spot where the aluminium felt different. That might have been a bit mistake :(. Still have the 2-3 flare at low speed when hot, but now also have a bumb/hard shift fram 3-4 some times. Also when hot. That bumb was bot there before. Need to add that I did a adaption of the Controle Module and had to drive like 2 hours and still could not complete 2-1 downshift or N-D garage shift but the rest flashed the triangle :). Well I might try Lucas Transmission fix before anything else, what I have read it wont hurt anything.



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vtl
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Re: B4 servo

Post by vtl » Wed Aug 14, 2019 6:09 am

Katten wrote:
Mon Aug 12, 2019 7:32 am
Is there any way of knowing how much longer the piston needs to be? Or to know if it needs to be longer at all. My piston has two bands running on the top cone.
Measure piston travel. Or just weld 0.5-1 mm :)


2005 XC70 250k
2016 XC60 40k

Katten
Posts: 19
Joined: Sat Aug 03, 2019 3:12 pm
Year and Model: S80 2002
Location: Sweden
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Katten

Re: B4 servo

Post by Katten » Thu Aug 15, 2019 4:09 am

I might weld the replacement piston and test once I get the time :). First I will add Lucas Transmission Fix and see what happens. If it does not fix anything the piston is the next item I will test :). If I get the transmission sorted an oil cooler and filter will be added too! :)



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