Rear Brakes Grabbing
Moderator: redstangbob
- Sierra John
- Posts: 206
- Joined: Tue Sep 04, 2012 1:01 am
- Location: Sierra Madre, Calif.
Rear Brakes Grabbing
When I apply the brakes, the rear end feels like it's crossing rows of uneven railroad tracks. The brakes are grabbing, there's a knocking noise, and the rear end shudders. I have to use the lightest pedal pressure possible. Used to just be when the car was cold. Now, it seems to be full time. What would you suggest checking first? I was wondering if it could be from oil getting on the brake linings.
1966 Town Hardtop
Re: Rear Brakes Grabbing
What year car? 65-66. proportioning valve?
- Sierra John
- Posts: 206
- Joined: Tue Sep 04, 2012 1:01 am
- Location: Sierra Madre, Calif.
-
- Posts: 519
- Joined: Tue Jan 20, 2015 12:24 pm
Re: Rear Brakes Grabbing
It’s a long way from my easy chair to your brakes that
Being said...I would pull the drums inspect for leaks and
Make sure everything is free and working , maybe clean
Stuff up with brake clean , quick adjust and back together.
Then a quick bleed . Ok stop ,if there are any signs of
Brake fluid ( peel the cups a little and look) fix it now.
A tiny bit of rear end fluid you can clean off and try.
This should narrow it down. The brake shoes and drums
Should basically be ok. Let’s get the rest figured out
First. I’ll be watching what you post. Thunderbirds are
My hobby. I work on cars and this is basic brake stuff.
Hope this is helpful.
Cliff
Being said...I would pull the drums inspect for leaks and
Make sure everything is free and working , maybe clean
Stuff up with brake clean , quick adjust and back together.
Then a quick bleed . Ok stop ,if there are any signs of
Brake fluid ( peel the cups a little and look) fix it now.
A tiny bit of rear end fluid you can clean off and try.
This should narrow it down. The brake shoes and drums
Should basically be ok. Let’s get the rest figured out
First. I’ll be watching what you post. Thunderbirds are
My hobby. I work on cars and this is basic brake stuff.
Hope this is helpful.
Cliff
Cliff Rankin
63 convertible
64 convertible
63 convertible
64 convertible
Re: Rear Brakes Grabbing
Hi Sierra. Agree with Cliff and would add one more wrinkle, which is that aftermarket brake shoes can result in the chattering you're experiencing. Did you change the brake shoes recently? I ran across this on my '64 when I replaced the front shoes with Centric aftermarket ones after turning the drums. The chattering upon braking was dangerous and frightening. My neighbor who is a long term Ford guy recommended I use Original Equipment brake shoes. After installing those, no more chattering. What I noticed about the OE shoes is the leading and trailing shoes for each wheel are different composition, whereas the Centric ones are same lining leading and trailing. As well, with the OE ones there is a groove cut into the leading shoe, presumably to shed water.
Doug
Doug
1964 TBird Hardtop
1974 Porsche 914 2.0
1974 Porsche 914 2.0
- Sierra John
- Posts: 206
- Joined: Tue Sep 04, 2012 1:01 am
- Location: Sierra Madre, Calif.
Re: Rear Brakes Grabbing
Thanks for all the replies. I appreciate it. The brake shoes have not been changed recently. Every time I have them inspected, they look good and have about 50% to 60% left. The guy I rely on for brake work isn't available for a couple of weeks, so I'll wait until he can inspect it. If the shoes/drums look normal, the proportioning valve could be the issue.
1966 Town Hardtop
-
- Posts: 519
- Joined: Tue Jan 20, 2015 12:24 pm
Re: Rear Brakes Grabbing
I think , let’s get to basics. Please keep us updated.
It’s a difficult diagnosis on the form and not being there
And seeing it. I would like to know the out come.
Please post the fix , or if you need to bump heads
Some more , please do so. Always here. Kinda wished
Karl would have chimed in on this. He has a totally different outlook on diagnosis. Love hearing different
Opinions.
Thanks
Cliff
It’s a difficult diagnosis on the form and not being there
And seeing it. I would like to know the out come.
Please post the fix , or if you need to bump heads
Some more , please do so. Always here. Kinda wished
Karl would have chimed in on this. He has a totally different outlook on diagnosis. Love hearing different
Opinions.
Thanks
Cliff
Cliff Rankin
63 convertible
64 convertible
63 convertible
64 convertible
Re: Rear Brakes Grabbing
The front being disc brake and the back drum brakes a proportioning valve is used to adjust the pressure between the brake system, it is located on the drivers side inside the engine compartment behind and down from the wheel well. If not scratch on the inside they can be rebuilt, kits are available.
-
- Posts: 49
- Joined: Sat Jul 06, 2019 11:19 pm
Re: Rear Brakes Grabbing
If 64ZCODE is stilled tuned in, can you tell us where you found the "Original Equipment" front brake shoes? I'm having the same problem even after having my brand new drums turned. Thanks.64ZCODE wrote: ↑Wed Sep 23, 2020 7:26 pm Hi Sierra. Agree with Cliff and would add one more wrinkle, which is that aftermarket brake shoes can result in the chattering you're experiencing. Did you change the brake shoes recently? I ran across this on my '64 when I replaced the front shoes with Centric aftermarket ones after turning the drums. The chattering upon braking was dangerous and frightening. My neighbor who is a long term Ford guy recommended I use Original Equipment brake shoes. After installing those, no more chattering. What I noticed about the OE shoes is the leading and trailing shoes for each wheel are different composition, whereas the Centric ones are same lining leading and trailing. As well, with the OE ones there is a groove cut into the leading shoe, presumably to shed water.
Doug
Re: Rear Brakes Grabbing
Sure redthunder, it was a while back but I believe it was from NOS Parts Ltd. If they don't have them they can probably direct you to someone that does:
https://nospartsltd.com/
https://nospartsltd.com/
1964 TBird Hardtop
1974 Porsche 914 2.0
1974 Porsche 914 2.0
Re: Rear Brakes Grabbing
I should mention the correct term is New Old Stock (NOS). Also, looks like the NOS Parts Ltd. website is being cranky so best to call them to confirm what they have in stock. I was able to get front and rear shoes for my '64.
1964 TBird Hardtop
1974 Porsche 914 2.0
1974 Porsche 914 2.0
-
- Posts: 49
- Joined: Sat Jul 06, 2019 11:19 pm
Re: Rear Brakes Grabbing
Thanks 64ZCODE - appreciate it!
- Sierra John
- Posts: 206
- Joined: Tue Sep 04, 2012 1:01 am
- Location: Sierra Madre, Calif.
Re: Rear Brakes Grabbing
Cliff: You wanted to know the outcome with my rear brakes. My brake expert finally checked it out. Everything looked normal. However, the drums have been machined to the max, and the adjustors are turned all the way. Is it possible the knocking I was hearing at the rear when applying the brakes was the adjustor slipping? Everything has been cleaned, so it seems OK for now. If the grabbing and knocking come back, I'll replace the drums and shoes.
1966 Town Hardtop
Re: Rear Brakes Grabbing
My rear brakes would grab when my axle started leaking oil into the drum.
1966 Thunderbird Convertible (Emberglo / White-Emberglo)
Modified 428 - stroked, rollercam, aluminum top end, headers
Livermore, CA
Modified 428 - stroked, rollercam, aluminum top end, headers
Livermore, CA
-
- Posts: 519
- Joined: Tue Jan 20, 2015 12:24 pm
Re: Rear Brakes Grabbing
I’m sorry for the untimely response. No would not think
So , but it’s possible. I can hear my back brakes when I hit
The peddle and it’s quite in my garage. Glad things
Worked out with a little maintenance.
Thanks
Cliff
So , but it’s possible. I can hear my back brakes when I hit
The peddle and it’s quite in my garage. Glad things
Worked out with a little maintenance.
Thanks
Cliff
Cliff Rankin
63 convertible
64 convertible
63 convertible
64 convertible