Welcome Guest. ( logon | register ) | ||||||
|
|
|
| Topic Tools | Message Format |
Author |
| ||
Jonathan Joseph Expert Date registered: Oct 2006 Location: Charleston, South Carolina Vehicle(s): 2004 G55 Posts: 1538 | Braking/Shifting/Vacuum??? problem Hey guys I need some help, I have had an intermitent braking problem for some time. Occasionally when I am backing (reverse) at idle speed I loose braking power. The brakes work but require tremendous force. This is usually when on an incline (nose up) Not all of the time just occassionally. This condition has persisted for months. Usually racing the engine in neutral has solved the problem. ( Vacuum??) Sometimes shifting gears forward/neutral/reverse helps. BUT TODAY.....I warm the truck up begin to drive, ...brakes no good, and.... low and behold she will not shift out of second gear. I stop, shift to neutral, rev engine shift back, accelerate, still second gear. Reverse, no good, park no good, SHUTDOWN ,RESTART ...maybe.... accelerate,...... then, brakes and shifts..what's up with this? A couple other pieces of info, Sometimes brakes are weak in forwartd gear also just seems more common in reverse at low speed and low rpm's. (Low speed/low rpm's in forward also) I think this problems only exists when vehicle is started from cold(ambient not cold-cold) Any ideas? I can provide more facts if neccessary, I'm sure someone here know's what this is all about. Thanks Jonathan | ||
#73848 | |||
Author |
| ||
DesertStar Expert Date registered: Apr 2006 Location: San Diego, CA USA Vehicle(s): 85-280GE/95-G320/08-G500 Posts: 2156 | RE: Braking/Shifting/Vacuum??? problem It sure sounds like you have a vaccuum leak somewhere in your shift linkage....curious as to whether your G stops immediatly when you turn the key off, or delays a few seconds. Irratic shifting, and motor not turning off immediately are tell tale signs of some type of leak in vaccuum system on Benz diesels. I would check all the lines going to your shift linkage at back of motor to see all is OK and work from there. My 300SD had the symptoms I described and turned out I had a vaccuum leak in one of my climate control vaccuum elements that work the defroster flap(not applicable to a G). Mike | ||
#73849 - in reply to #73848 | |||
Author |
| ||
Jonathan Joseph Expert Date registered: Oct 2006 Location: Charleston, South Carolina Vehicle(s): 2004 G55 Posts: 1538 | RE: Braking/Shifting/Vacuum??? problem Mike, My engine doesn't stop like I would like it to when the key is turned off. It gives a little bit of a death rattle, shakes and then stops. I will trace all vacuum lines as best I can. The strange thing to me is that it is intermittent. BTW thanks for your advice and info on the tranny shifting situ. Maybe related for me. Jonathan | ||
#73852 - in reply to #73848 | |||
Author |
| ||
Merz-Ben Extreme Veteran Date registered: Aug 2006 Location: Floyds Knobs, IN 47119 Vehicle(s): 230G, U1200, U1250 DoKa, U1300L, U1500, U1700, 416 Posts: 377 | RE: Braking/Shifting/Vacuum??? problem Jonathan, Sounds to me like either the vacuum pump or the brake booster is on it's way out. It could be either, as the booster can intermittantly loose vacuum and cause a large leak, then it eventually won't hold vac at all. Usually the Vac pump itself doesn't intermittantly fail, but it is possible, especially since RPM increase remedies the problem sometimes. Next time you have the symptoms, open the hood and check some of the accessable lines for vacuum and/or check for a sucking noise next to the master cylinder. I doubt that the leak causing your problem would be in one of the lines, since a line leak would usually be constant. Cheers, Ben | ||
#73857 - in reply to #73848 | |||
Author |
| ||
Jonathan Joseph Expert Date registered: Oct 2006 Location: Charleston, South Carolina Vehicle(s): 2004 G55 Posts: 1538 | RE: Braking/Shifting/Vacuum??? problem Thanks Ben, that's what I was thinking, a real leak would be full time. I didn't want to hear that the booster was bad. Nooooo..... The vacuum pump is gear driven no? I'm embarressed I don't know that, should have looked at the book or engine first.....but it's outside the front door, way to far to walk... Jonathan | ||
#73858 - in reply to #73848 | |||
Author |
| ||
Merz-Ben Extreme Veteran Date registered: Aug 2006 Location: Floyds Knobs, IN 47119 Vehicle(s): 230G, U1200, U1250 DoKa, U1300L, U1500, U1700, 416 Posts: 377 | RE: Braking/Shifting/Vacuum??? problem The vacuum pump is driven off of a setup similar to a cam lobe on the front of the injection pump gear. It isn't that big of deal to take off, there are 6 internal hex bolts that take a 5mm alen key and one line, and the vac pump comes right off the engine. You might want to do a vac test on it and see what it is pulling before you take it off (i don't remember the figure, once you work on so many of these things you get a feel for what the vac should be ). The pumps are pretty common because they are the same as a sedan, I'm sure you could find a used one local (or I'm sure I've got a spare or two), or get a new one without too much trouble. I think a rebuild kit is also avalible for them, but I've seen quite a few with the drive arm worn out or broken... and can't be rebuilt. If it is the booster, I think I've got a spare used one on a parts truck if you are cheap like me and don't want to buy a new one . Cheers, Ben | ||
#73860 - in reply to #73848 | |||
Author |
| ||
dai Expert Date registered: Apr 2006 Location: Oregon USA Vehicle(s): 300GD 300TD BMW R100RS Landini 80F Posts: 2110 | Re: Braking/Shifting/Vacuum??? problem If it is the pump and the drive arm is not worn out the diaphragm is an inexpensive part and easy to install. It does not require the removal of the whole pump housing. Isolate the problem first. See if the pump is pulling vacuum before replacing stuff. -Dai | ||
#73905 - in reply to #73848 | |||
Author |
| ||
hipine Date registered: Jul 2006 Location: US, CO, Bailey Vehicle(s): 460 1980 280GE w. 617A | RE: Braking/Shifting/Vacuum??? problem You have a Mitey-Vac unit? If not, get one. Isolate the different vacuum elements and test them one at a time to see where the leak is at. Could be anywhere. -Dave G. | ||
#73961 - in reply to #73848 | |||
Author |
| ||
Warren T Extreme Veteran Date registered: May 2006 Location: Montreal Vehicle(s): 230GE,300GD,300D Posts: 519 | RE: Braking/Shifting/Vacuum??? problem Intermitant vacuum problems are usualy caused by the little check valve at the exit of the pump, clean it and veryfi that the hair spring is not broken. If you have to remove the pump check condition of cam lobes and roler bearing. Cheers Warren | ||
#74118 - in reply to #73961 | |||
Author |
| ||
Jonathan Joseph Expert Date registered: Oct 2006 Location: Charleston, South Carolina Vehicle(s): 2004 G55 Posts: 1538 | RE: Braking/Shifting/Vacuum??? problem Thanks for all the good advice guys. I'll be sure to post the solution when I have it figured out. Thanks | ||
#74187 - in reply to #73848 | |||
« View previous thread :: View next thread » |
|
|