Few weeks ago the trunk motor on my 86 Firebird failed. It's not remote one so I turned key on the trunk lock, lid popped open and up but there was no buzz of lock assembly moving to the top position. Luckily I was at a HW store so I got some duct tape and made it home with trunk taped down. When inspecting things I took off the rear panel and knocked the motor with a wrench and suddenly it buzzed back to up position and it has been working for the two or three times that I dared to test it after that. Now a new motor assembly is hideously expensive here in Finland and I'm a bit short of cash so I was wondering if I could DIY fix things? I'm assuming the problem is with the motor since knocking it made it work again. I read that this knocking usually frees up the worn out brushes so it's temporary fix only, right or wrong? The trunk motor fixing PDF on this site says not to remove the cylindrical motor cover, I guess I should do that to change the brushes so any ideas what horrible things will happen if I take the cover off? Or am I doing a faulty diagnosis here?

 

Could be the motor, could be the slides deteriorating enough to cause the assembly to bind, could be the reversing/T switch contacts are dirty/worn/burnt not allowing for good conductivity. Unfortunately the hatch pull down assembly is fairly complex and sometimes you need to completely tear it down to determine the root cause.

 

I took the cover off and was able to get it back on.
There isn't a system in place to hold the brushes while you reassemble. I used my finger on one side and a small screw driver on the other. It's cumbersome but can be done.
I cleaned all the contacts and reassembled and it worked fine for a couple of weeks.
I then replaced it and now works as it should

Top Down Solutions who is a member and the local expert, he will talk you through all the trouble shooting to diagnose the problem.. He is also a supplier for the repair parts. He's who I bought all the repair parts from.
https://top-downsolutions.com/

You can call and speak with him. He's very patient and easy to deal with.

 

Thank's for the replies, I need to take the motor off and see what's going on with it. Although that's not on the top of my to-do list. I finally got the Holley Sniper setup running nice so I'll just enjoy driving the car for a while.