Chris Martin
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• Berwyn, IL, USA |
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• Registered on 2/2/2003 |
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• 5 posts |
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 Posted:4/13/2003 11:36 |
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Some of you may remember this issue from the old site. My truck will not steer from standing stop with brakes on hard. Ford says it is a normal problem and will not fix(has tech sheet listed). It seems that this truck may have something called Hydrobrakes,which uses Power steering pump for power brake assisit?. Stopped with foot hard on brake on hard pavement it feels like no power steering. You can hear the Power steering pump un-loading(dumping). Pick-up lightly on pedal and systems work, But just a hair more up, and your on the roll.(ice or mud wheels turn fine no matter how hard pedal is pushed.
Hydro is normal on BIG truck with an oil burner under hood because of no or little vaccumn developed, and may be used by ford to make engine swaping less work on them.
Would like to explore if and how system are inter-linked. If not how can I boost pump output pressure (gota be away). Big tires could cause same issues but my truck is stock. lookin for any ideas and diagrams of systems. |
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monsta
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• The Big Island, HI, USA |
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• Registered on 1/5/2002 |
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• 1,056 posts |
• 2
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Posted:4/14/2003 00:49 |
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| Quote: | It seems that this truck may have something called Hydrobrakes,which uses Power steering pump for power brake assisit?.
Hydro is normal on BIG truck with an oil burner under hood because of no or little vaccumn developed, and may be used by ford to make engine swaping less work on them.
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All diesel trucks use the power steering pump to "power" their brakes. (With the exception of air braked trucks.)
Diesel engines do not develop vacuum since there is no throttle plate.
| Quote: | Stopped with foot hard on brake on hard pavement it feels like no power steering. You can hear the Power steering pump un-loading(dumping). Pick-up lightly on pedal and systems work, But just a hair more up, and your on the roll.(ice or mud wheels turn fine no matter how hard pedal is pushed.
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Some Super Duty's experience this and some do not. A search over at Ford-trucks.com in the Super Duty forum may help. Some have fixed the problem with suspension alterations.
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Chris Martin
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• Berwyn, IL, USA |
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• Registered on 2/2/2003 |
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• 5 posts |
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Posted:4/19/2003 10:21 |
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Thanks monsta for reply.Here is what I have found by hands on diggin. The Pig is standard vac brake. If the sterring wheel is at rest you can feel the fluid coming back to the pump system. If you push down on the brake pedal(hard) and turn the wheel the return line coming back to the PS tank goes dead (no flow). If I pinch off the power steering return line the wheel also becomes hard to turn. The ps pump looks to have no external adjustment and other than steering play adjuster on top of the gear box it has nothing. With that said have pricing pulled for new PS pump and looking for exploded view of sterring gear box. My guess at this time is the pump may no be producing enough pressure, or the steering gear box does not have enough guts to move the Pig tires. Since I do not find this true with all EX,s I gotta believe it is an adjustment somewhere. Got any Ideas? Have a friend that is contacting 4X4 custom shop to find out how they deal with Monster tires and how they soup-up steering system. The pig must be able to turn with the brake on. Ford Motor refuses to fix, but know of the problem? |
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