1990 GMC K1500 restoration

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HillcrestFarm

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Third attempt at trying to address the soft brake pedal. After lots of reading, I’m starting to think the rear wheel abs unit is the issue, specifically a leaky dump valve allowing fluid to leak into the accumulator rather than apply pressure to the rear brakes. This is a great article describing the operation of the rear wheel abs system:

https://www.aa1car.com/library/abs_kelseyhayes_rwal.htm

I also noticed that my combination valve was leaking a little bit of fluid out of the metering valve so I decided to replace it along with the rear wheel abs unit. Unfortunately, the “AC Delco inspired” combination valve that I purchased is leaking out of the electrical connector on top and the brakes are now probably worse than where I started. Currently sourcing a used combination valve to replace this crappy knockoff valve. The brakes will have to wait until the new valve arrives.

YouTube video:
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Great video series. Thank you.

Here is a link to pdf of the service manuals and other manuals. You might find the brake manual interesting too.

https://www.gmt400.com/threads/88-95-service-manuals.43575/


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idlook2

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Got mine on EBay ( old dealer NOS) Check there also. Moog HD one is the best option for 2 bolt Idler arms.
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I picked up my idler arm from rockauto for around $55. Moog makes three different flavors:

Regular: https://www.moog-suspension-parts.com/moog-k6331

Heavy Duty: https://www.moog-suspension-parts.com/moog-k6390

Super Duty: https://www.moog-suspension-parts.com/moog-k6483t

I bought the “Super Duty” model but it’s not totally clear what the differences are between the models. My guess is larger bushings and thicker castings?
 

idlook2

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You should do a video around your shop. Would be interesting seeing the lift, etc. I must say I am pretty envious..

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My shop is just an extra deep single stall (~28 ft deep) with a Rotary Revolution 4 post lift and a bridge jack. I always wanted a lift and finally bought one about 4 years ago. Installed it myself in about a day. I’ve used it a ton. Before kids, I did a lot of work on sports cars prepping them for track days.

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90 Silverado

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I picked up my idler arm from rockauto for around $55. Moog makes three different flavors:

Regular: https://www.moog-suspension-parts.com/moog-k6331

Heavy Duty: https://www.moog-suspension-parts.com/moog-k6390

Super Duty: https://www.moog-suspension-parts.com/moog-k6483t

I bought the “Super Duty” model but it’s not totally clear what the differences are between the models. My guess is larger bushings and thicker castings?



That's the one I got ( superduty aka problem solver ) got mine for $45. It's way beffer than my stock original. Check out my post in the stock suspension forum here titled "Idler Arm".
 
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