Scraping sound at high speed only when accelerating

[coachhomer]

I just noticed a scraping sound when I speed up at speeds above 50mph. Sounds like it is coming from the front left hub assembly but I just replaced the hubs about 3 months ago. It is a grinding sound and only happens when I hit the gas. Any ideas?

Thanks!

C

 

[The Car Stereo Company]

4wd vacuum lines......

 

[coachhomer]

4wd vacuum lines......

How hard to replace those?


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[FordTechOne]

I just noticed a scraping sound when I speed up at speeds above 50mph. Sounds like it is coming from the front left hub assembly but I just replaced the hubs about 3 months ago. It is a grinding sound and only happens when I hit the gas. Any ideas?

Thanks!

C

What year is the truck?

Grinding from the front hubs under acceleration indicates that you're losing vacuum to the IWEs. That can be caused by a number of things including a leaking vacuum line, faulty check valve, leaking solenoid, leaking vacuum reservoir, etc.

If you are out of warranty, you can diagnose the system pretty easily with a basic vacuum pump from harbor freight.

 

[coachhomer]

Thank you. Will be working on it today.


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[The Car Stereo Company]

How hard to replace those?


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check the line to see if its damaged. mine had visible damage. its simple to replace the hose. the oem hose is 2 hoses molded into 1. looks like an 8. i bought 2 hoses since they were different size and i couldnt find the oem style anywhere.

 

[coachhomer]

Do you just disconnect it here? And then test both directions?


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[The Car Stereo Company]

Do you just disconnect it here? And then test both directions?


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yep. theres a joint a little further up where you can seperate it. but that hose just pulls off right where you indicated

 

[coachhomer]

yep. theres a joint a little further up where you can seperate it. but that hose just pulls off right where you indicated

Sorry for all of the questions. Can I just disconnect it and drive until I have time to fix it?


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[The Car Stereo Company]

i dont think you should. the 4wd vacuum system works by using vacuum pressure to engage 2wd. it defaults to 4wd when theres no vacuum pressure. a quick test would be to drive in 4wd and see if the noise goes away. just do it in a straight line though. dont want to turn on pavement in 4wd