Need Help with rear end

[Billybeau1]

My 74 coupes rear end klunks when I put the car in gear. Its a pretty good klunk so I dont think its a u-joint on the drive shaft. I'm gonna crawl under ther and check but if it is the rear end what are my options? I'm pretty handy with the tools. Any advice would be appreciated.

Bill

 

[Stingray6974]

Bill,

It's most likely a bad front diff mount cushion. You can see the lower cushion between the frame and diff mount. Reach over the top and should feel the upper cushion peeling out or gone altogether.

Mike

 

[Evolution1980]

It's most likely a bad front diff mount cushion.

I'm with Mike on this one. I used to get a real nasty slamming sound when my car would hit third gear when I wasn't on the gas. My rear end diff had been leaking for a LONG time and it completely destroyed the bushing that mates up the diff to the crossmember. Got that replaced and everything is good now.

However, your initial thought could be correct to, as when I first bought my car, the U-joints were shot. When I had them off, you could actually see where years of wear had actually created depressions in the joints. So when the car would be put in gear, the half-shaft would rotate just a hair and seat itself into that depression, hence the 'clunking' I was hearing. (...or something like that...)

 

[Billybeau1]

Thanks guys. This week I'll crawl under there and check the easy stuff first.

Bill

 

[74bigblock]

My car actually thunks a bit too when I put it in gear.... and it also squats down as it goes in gear. Dunno why... but it hasn't bothered me yet!

 

[Bob Chadwick]

The squatting is normal. It was explained to me as being due to the way the independent suspension works.

My clunk went away as well when I replaced the bushing Mike suggested.

 

[74bigblock]

you know... Bill, this thread sounds kinda strange now that I think about it.... Do you really need help with your rear end??? :booty





I couldn't resist!

 

[74bigblock]

Maybe since we are both in IL, and both our rear ends are clunking... we can schedule a Corvette Colonic and go together?!

 

[Billybeau1]

;lol ;lol ;lol

 

[Billybeau1]

Damn did it again :duh

 

[Evolution1980]

Damn did it again :duh

Umm, you know you can go back and edit your own posts...you don't have to repost...
Just look at your previous posts and you'll see a little link that says "edit"....

 

[74bigblock]

Umm, you know you can go back and edit your own posts...you don't have to repost...
Just look at your previous posts and you'll see a little link that says "edit"....

Are you saying Bill has issues with his front end too?

 

[Billybeau1]

Umm, you know you can go back and edit your own posts...you don't have to repost...
Just look at your previous posts and you'll see a little link that says "edit"....

Did not know that :duh Thanks The only issues I have is the keys on my keyboard keep moving on me. :CRASH

 

[Billybeau1]

Found the problem with the rear end clunk...... U-joints fine, bushings fine. The master cylinder was not pumping fluid to the rear calipers. All I had was front brakes. Replaced master cylinder and problem went away..... Ya learn something new every day I guess. :duh

 

[Evolution1980]

Found the problem with the rear end clunk...... U-joints fine, bushings fine. The master cylinder was not pumping fluid to the rear calipers. All I had was front brakes. Replaced master cylinder and problem went away..... Ya learn something new every day I guess. :duh

Clear me up on this... How did the master cylinder, or lack of rear brakes, account for a clunking sound in the rear?

 

[Billybeau1]

Well I think what I was hearing was the back wheels breaking loose for a second before I applied more pressure on the brakes to keep the car from moving. Since the rear calipers were not engaging, their was nothing to hold the wheels when I put the car in drive. Anyway thats the only thing he did and the problem is gone.

 

[Evolution1980]

Well I think what I was hearing was the back wheels breaking loose for a second before I applied more pressure on the brakes to keep the car from moving. Since the rear calipers were not engaging, their was nothing to hold the wheels when I put the car in drive. Anyway thats the only thing he did and the problem is gone.

I don't know, bud... I gots me a strange feeling that your problem has only temporarily disappeared.
I guess a simple way to check your theory would be to have the car in neutral, not moving, off the brakes. Then drop it into drive and see if it clunks again.
Also, you could put the brakes on, put the car in reverse, then (still holding the brakes) quickly put the car into drive and see if it clunks.

Ah reckon I's don't knows much about these here cars, but sumthin just don't quite add up ta me...

Did he put new pads in the rear or adjust the rear calipers? Or was the master cylinder absolutely the only thing he replaced?

 

[Billybeau1]

Did he put new pads in the rear or adjust the rear calipers? Or was the master cylinder absolutely the only thing he replaced?

The pads were fairly new. Just the master cylinder and bled the brakes. I'll have to admit I was skeptical too when he called but hearing is believing... Its gone thats for sure. Thanks for your input as I do realize a lot of people get ripped off. If he did do something else, he didnt charge me for it.