DYI - wing hydraulic sync and bleed
05-13-2012, 02:42 PM
#1
DYI - wing hydraulic sync and bleed
I see a lot of this.......here's what worked for me. KEY POINT is that oil leaking from one ram may will go away in a well balanced and operatiing system and stay away......it did for me.
Forget the external cleaning........the real crud is down in the rams where you can get at it.
NOTE: a small film of hydr. oil coats the rams (small pin rams inside the big chrome slides you can see outside) and some very small evaporation takes place with use.........over 7-10 years, this evaporation eventually will cause an out of sync condition when you've never had a single drop of oil leakage. Once out of sync, the system tends to push oil through the sael on one or the other of the ramss due to high loading on one side. The crud that tends to stick the chrome sides doesn't help a bit......but may not be the real problem in most cases.
Here's the sequence to fix:
1) raise the wing and then renmove it........lots of other posts on wing removal.
2) lower the rams, and remove their upper snap rings to get them apart. This can be done in or out of the car, feel free to open the hoses........we'll re-bleed next. CAREFUL: There are springs inside (used to help retract the rams).......no dangerous load when the rams are retracted.
3) Clean the Chromed external sliding surfaces of the rams and the I.D.'s of their mating sleeves. This is where youi'll find the crud you can get at otherwise. I wouldn't lube beyond maybe a light rub with a silicone spray...certainly nothing that will collect dirt like a greese or oil. Put the rams all back together. Don't install the wing.
4) Flush and re-bleed:
a) Uncover the hydr. pump under the deck lid so you can apply an external power source. Note a battery charger will do it and note that swapping the input polarity reverses the direction of the pump.
NOTE: the pump is really two syringes driven in parallel by a motor driven screw..........this is how it synchroniozes the two rams........out of snyc rams means one side has less fluid in it than the other.....simply, the fliud colums are different in length.
b) Submerge both of the open hose ends (the ram end banjos) in a few ounces of fresh hydraulic oil (as used for power steering and for the small hydraulic brake reservoir up front). A clear container is good so you can see the fluid exchange and when the air is blead out.
c) Cycle the motor back and forth until all the air is out. CAUTION: don't over heat the electric pump motor.
NOTE: the total oil volume in the pump is very small..........maybe an ounce or so........so don't expect any big flow or spray here, and the fact that the flow is very small doesn't mean the pump is shot either.
d) With the hose ends STILL submerged in the oil.........retract the pump .......i.e. draw in a full fluid charge. KEEP the hose ends submerged.
d) Reconnect the hoses to the rams; A spare pair of hands hepls but yopu can do it alone too. Just have your self set up so that you loose the least oil from the dripping hose end as possible as you pull the hose end out of the oil container and get the banjo bolt and washeras screwed in. Do one hose after the other keeping the second one submerged until you are ready to connect it up. Some loss is inevitable and no big deal.
e) cycle the rams up/down 6-8 times.........their operation will become consistent.......although they will probably be out of sync. due to different oil loss during the two hose connections.
f) Sync the two rams: Realize that the big springs are pusing the Chrome rams down......and the oil in the hose/pump is pushing them up aginst the spring load. So following the manual more or less;
f1) raise the rams to a mid point.
f2) on the ram that sticks up the highest, crack the banjo bolt on its end allowing the ram spring to force to bleed bit of oil out as the ram lowers matching the height of the other........go back and forth a bit until they are within about 2 mm or 1/16 inch of each other........perfection is nice, but not required.
NOTE: If you let too much oil out.........refill the pump per e)above and start over.
g) Cycle the rams up and down to be sure they remain pretty closely synced........and re-install the wing.
NOTE: you'll end up with oil all in and over the rams and it may appear to leak.........drive and clean with the black covers on the bottom over the banjo bolts off for a week or two to be sure you either really do have a leaky ram........or just long term 'run off'.
Again; these leaks go away when well blead and synced..........at least they did for me. I did my daily driver over a year ago and its fine and dead dry today.
Best of luck. MK19
Forget the external cleaning........the real crud is down in the rams where you can get at it.
NOTE: a small film of hydr. oil coats the rams (small pin rams inside the big chrome slides you can see outside) and some very small evaporation takes place with use.........over 7-10 years, this evaporation eventually will cause an out of sync condition when you've never had a single drop of oil leakage. Once out of sync, the system tends to push oil through the sael on one or the other of the ramss due to high loading on one side. The crud that tends to stick the chrome sides doesn't help a bit......but may not be the real problem in most cases.
Here's the sequence to fix:
1) raise the wing and then renmove it........lots of other posts on wing removal.
2) lower the rams, and remove their upper snap rings to get them apart. This can be done in or out of the car, feel free to open the hoses........we'll re-bleed next. CAREFUL: There are springs inside (used to help retract the rams).......no dangerous load when the rams are retracted.
3) Clean the Chromed external sliding surfaces of the rams and the I.D.'s of their mating sleeves. This is where youi'll find the crud you can get at otherwise. I wouldn't lube beyond maybe a light rub with a silicone spray...certainly nothing that will collect dirt like a greese or oil. Put the rams all back together. Don't install the wing.
4) Flush and re-bleed:
a) Uncover the hydr. pump under the deck lid so you can apply an external power source. Note a battery charger will do it and note that swapping the input polarity reverses the direction of the pump.
NOTE: the pump is really two syringes driven in parallel by a motor driven screw..........this is how it synchroniozes the two rams........out of snyc rams means one side has less fluid in it than the other.....simply, the fliud colums are different in length.
b) Submerge both of the open hose ends (the ram end banjos) in a few ounces of fresh hydraulic oil (as used for power steering and for the small hydraulic brake reservoir up front). A clear container is good so you can see the fluid exchange and when the air is blead out.
c) Cycle the motor back and forth until all the air is out. CAUTION: don't over heat the electric pump motor.
NOTE: the total oil volume in the pump is very small..........maybe an ounce or so........so don't expect any big flow or spray here, and the fact that the flow is very small doesn't mean the pump is shot either.
d) With the hose ends STILL submerged in the oil.........retract the pump .......i.e. draw in a full fluid charge. KEEP the hose ends submerged.
d) Reconnect the hoses to the rams; A spare pair of hands hepls but yopu can do it alone too. Just have your self set up so that you loose the least oil from the dripping hose end as possible as you pull the hose end out of the oil container and get the banjo bolt and washeras screwed in. Do one hose after the other keeping the second one submerged until you are ready to connect it up. Some loss is inevitable and no big deal.
e) cycle the rams up/down 6-8 times.........their operation will become consistent.......although they will probably be out of sync. due to different oil loss during the two hose connections.
f) Sync the two rams: Realize that the big springs are pusing the Chrome rams down......and the oil in the hose/pump is pushing them up aginst the spring load. So following the manual more or less;
f1) raise the rams to a mid point.
f2) on the ram that sticks up the highest, crack the banjo bolt on its end allowing the ram spring to force to bleed bit of oil out as the ram lowers matching the height of the other........go back and forth a bit until they are within about 2 mm or 1/16 inch of each other........perfection is nice, but not required.
NOTE: If you let too much oil out.........refill the pump per e)above and start over.
g) Cycle the rams up and down to be sure they remain pretty closely synced........and re-install the wing.
NOTE: you'll end up with oil all in and over the rams and it may appear to leak.........drive and clean with the black covers on the bottom over the banjo bolts off for a week or two to be sure you either really do have a leaky ram........or just long term 'run off'.
Again; these leaks go away when well blead and synced..........at least they did for me. I did my daily driver over a year ago and its fine and dead dry today.
Best of luck. MK19
05-14-2012, 10:36 AM
#3
Rennlist Member
Glad you had success in bleeding. I replaced a leaking ram, worked on the bleeding process for 2 days and never could get it fully bled. As you said the oil volume is so little that cracking the banjo bolt looses enough pentosin to make you refill again. I gave up and replaced the entire assembly. Congrats. glad to hear of your success.
