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-   -   When truck stops and go to accelerate I have a release of energy ? (https://67-72chevytrucks.com/vboard/showthread.php?t=825261)

truckin 79 08-27-2021 03:19 PM

When truck stops and go to accelerate I have a release of energy ?
 
So when I come to a stop and then push gas to start going again it feels like something lets go or releases. This has happened ever since my dad gave me this truck. I was thinking it was brake related so I have changed front pads to ceramic, new rotors, new rear shoes, new rear wheel cylinders as well as new rear drums. The only thing I have not changed is front calipers but put new blender screws to bleed them properly. I have changed all shocks as well. I was kind of thinking drive shaft u-joints but feel solid when trying to turn by hand. I Anyone else have any other ideas on what I should look at? I was going to look at rear shoes and see of maybe I switched shoes but have not done that yet.

sick472 08-27-2021 03:57 PM

Re: When truck stops and go to accelerate I have a release of energy ?
 
Possibly a rubber brake hose collapsing causing the brakes to hold until the go pedal jars them loose.

sick472 08-27-2021 04:05 PM

Re: When truck stops and go to accelerate I have a release of energy ?
 
Jack it up off of all fours (maybe just front or back to start with if your short of jack stands), start it, apply brakes firmly, put it in neutral, turn it off (in neutral), and see if any of the wheels won't spin.

Corts60 08-27-2021 06:08 PM

Re: When truck stops and go to accelerate I have a release of energy ?
 
Quote:

Originally Posted by sick472 (Post 8963440)
Jack it up off of all fours (maybe just front or back to start with if your short of jack stands), start it, apply brakes firmly, put it in neutral, turn it off (in neutral), and see if any of the wheels won't spin.

x2. While its up in the air, double check u-joints. When tires on the ground and trans in park, sometimes the u-joint can be bound up to feel tight, when it actually isn't.

Dead Parrot 08-27-2021 06:59 PM

Re: When truck stops and go to accelerate I have a release of energy ?
 
Other things to check: Motor and transmission mounts, Rear spring bushings, Rear spring u-bolts.

Pull the rear differential cover and check gears for damage.

cadillac_al 08-28-2021 09:45 AM

Re: When truck stops and go to accelerate I have a release of energy ?
 
I always check my brake operation in my driveway or anyplace with a slight grade. I apply the brakes and release them and the vehicle should roll easily. I will try this a few times. If the vehicle doesn't roll easily then something is sticking.

Nick_R_23 08-28-2021 12:01 PM

Re: When truck stops and go to accelerate I have a release of energy ?
 
Just by the sound of your post, I would be inspecting the master cylinder, and booster.

Also +1 for jacking the truck up in neutral and inspecting parts. Are you sure you aren’t just experiencing the drivetrain slack being taken up? When you coast to a stop (let off the gas) everything in the drivetrain gets loaded the opposite direction. Many things such as internal transmission components (such as sun shells), splines on shafts and yokes, and clearances on gearsets can all wear over time and create slack in the drivetrain. Once you load the drivetrain the opposite way (slowing down from moving forward and reversing create a similar effect), then apply the gas to move forward again, all of these components have to rotate slightly before they become loaded in the forward direction again, creating a feeling of delayed movement from the time the gas is pressed to when the truck actually moves. Excessively worn or aged parts will make this effect worse over time.

truckin 79 08-30-2021 06:33 PM

Re: When truck stops and go to accelerate I have a release of energy ?
 
It could just be old age, it takes me a second to get going the older I get lol. I think I will change the hoses and possibly master cylinder and see of this changes things at all. My brake hoses are probably original and should be changed for safety reasons.

LT7A 08-31-2021 04:56 AM

Re: When truck stops and go to accelerate I have a release of energy ?
 
I appreciate seeing all the input on this. trucking 79, if you get the chance to tell us how it goes as you check things out, that would be great.

84 400 09-01-2021 10:33 AM

Re: When truck stops and go to accelerate I have a release of energy ?
 
Has the truck sat unused for long period of time??

Sounds like one of two things to me.

The first is an internally collapsed rubber brake hose. There are three on your truck. One at each front wheel from the caliper to the frame and one from the frame to the rear axle. They collapse inside and do not allow fluid to return to the master thus holding your brakes. If those hoses are orgibal they should be replaced. Sometimes they will swell or crack.

Also a rusty caliper or caliper pin bushings could cause this. Again a hanging caliper. The piston should push back into the caliper fairly easy to its seated position. If it does not that could be a sign of rust.

Stock torque converter?

Mathew21 09-01-2021 10:42 AM

Re: When truck stops and go to accelerate I have a release of energy ?
 
As already mentioned a few times I suspect internally collapsed rubber brake hose.

truckin 79 09-02-2021 11:01 AM

Re: When truck stops and go to accelerate I have a release of energy ?
 
I just ordered all 3 brake hoses and a new master cylinder so will report once I get these put on. The best part is Rockauto is delivering in my area again so it only cost me 70 dollars for all 4 items. :metal:
On a side note I tried doing a panic stop at about 30 mph the other day and brakes did not lock up and truck stopped but took longer then I thought it should. Hopefully soon I will have working AC and good/better working brakes


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