Rod too long ? Brakes locked up - Team Camaro Tech
Brakes, Suspension & Steering Conversion questions, Steering & Handling

Reply
 
LinkBack Thread Tools Display Modes
post #1 of 16 (permalink) Old Jul 15th, 10, 12:59 PM Thread Starter
Tech Team
Bri
 
Join Date: Apr 2007
Location: ma
Posts: 69
Rod too long ? Brakes locked up

Hello,

After installing from discs, new master cylinder, new lines all around, proportioning valve and the longer of the two rods that came in the kit ( that i think i ordered from Matts - - it was over a year ago that i ordered it and just go to installing it a month ago). The brakes locked up. I was about two miles away from my house with a 2yr old and wife in the car and i needed to get home so i kept on driving eventhough the brakes were definitely on pretty hard. when i got home smoke was pouring out from all 4 wheels. it was bad.

I never replaced the rear brakes, just bled them after installing the new lines. After installing all the new parts the brake pedal never really felt right. It would only go down about 2 inches and then it would stop as if i were hitting something. From the instructions i could has sworn i was supposed to use the long rod but now i am begining to think i was wrong. I can't imagine why else the back breaks would lock up ( or drag to such extremes) when all i did was replace the lines.

I am nevervous to take off the wheels to see what damage i may have caused by driving it home. Unfortunately - it was better option that getting stuck on the side of the road and missing the wedding we had that day.....trust me.

Is there anything i can do / check before pulling the brake pedal off, the MC out, popping off the lines, and switching the rods ( it will take me 3-4hrs). I have never done anything with the proportioning valve. Should I ?

Thanks
Brian
plum_crazy_purple is offline  
Sponsored Links
Advertisement
 
post #2 of 16 (permalink) Old Jul 15th, 10, 01:31 PM
Senior Tech
Steps
 
Join Date: Dec 2005
Location: New Zealand
Posts: 13,316
Re: Rod too long ? Brakes locked up

Quote:
I am nevervous to take off the wheels to see what damage i may have caused by driving it home. Unfortunately
Damage...replace all the gease in the bearings and check the bearings
May have to get the drums/discs skimmed

The search button is your best friend.....
just back the MC bolts off and the brakes should release....depending on if nothing has 'welded ' due to very hi temps.

My Spelling is not incorrect...it is creative

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Steptoe is offline  
post #3 of 16 (permalink) Old Jul 17th, 10, 06:09 AM Thread Starter
Tech Team
Bri
 
Join Date: Apr 2007
Location: ma
Posts: 69
Re: Rod too long ? Brakes locked up

unbolting the the MC bolts will just release the brakes and not solve the problem. i can't imagine what else other than the rod being too long that would cause the rear brakes to lock up as well - when i never did anything to them other than to replace the lines and bleed them.
plum_crazy_purple is offline  
 
post #4 of 16 (permalink) Old Jul 17th, 10, 04:50 PM
Senior Tech
Steps
 
Join Date: Dec 2005
Location: New Zealand
Posts: 13,316
Re: Rod too long ? Brakes locked up

If backing off the mc releases the brakes then that is most prob the issue...
Older threads tell you how to measure the depth in the back of the mc (there are several depths) and the pin.
What can happen is the rears drag after 1st use due not being able to return get hot, espec if newly adjusted up also, and expand lock on a bit tighter...we are talking thous of an inch here and that is all it takes.
If replacing a mc, always measure distance and pin never assume it is right.

My Spelling is not incorrect...it is creative

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Steptoe is offline  
post #5 of 16 (permalink) Old Jul 18th, 10, 06:09 AM
Moderator
Kevin
 
KevinW's Avatar
 
Join Date: Jul 2000
Location: Millstone, NJ
Posts: 11,001
Re: Rod too long ? Brakes locked up

I know its too late, but for everyone who is getting the repro MC kits, it is very important for you to check the rods, besides choosing long or short. Test fit the MC to the booster with the rod of your choice. If you have a gap between the MC and the booster, you need to grind the rounded end of the rod. I had to take about 1/8 in off, in multiple tries. You should be able to put the mc on the booster without nuts and have it fully seat without any pressure. If you have a gap or can still rock it gently by hand, you need to grind some more. I just took a 4" grinder and kept shaping the rounded end. After that the brakes are working fine.

Also make sure the pedal rod is in the LOWER hole!

Hope there is not permanant damage.

Kevin


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
KevinW is offline  
post #6 of 16 (permalink) Old Jul 18th, 10, 06:16 AM
Gold Lifetime Member
Tom
 
Join Date: Mar 2008
Location: the 02176
Posts: 5,974
Re: Rod too long ? Brakes locked up

Quote:
Originally Posted by KevinW View Post
I know its too late, but for everyone who is getting the repro MC kits, it is very important for you to check the rods, besides choosing long or short. Test fit the MC to the booster with the rod of your choice. If you have a gap between the MC and the booster, you need to grind the rounded end of the rod. I had to take about 1/8 in off, in multiple tries. You should be able to put the mc on the booster without nuts and have it fully seat without any pressure. If you have a gap or can still rock it gently by hand, you need to grind some more. I just took a 4" grinder and kept shaping the rounded end. After that the brakes are working fine.

Also make sure the pedal rod is in the LOWER hole!

Hope there is not permanant damage.
Thanks for this advice, Kevin! I have a brake swap coming up and this is what I need to know.

'67 rs - ordered new by my Grandfather
327 L30, K-K, Deluxe int, tach & gauges, 12 bolt posi, 4 speed.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
-
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Melrose RS is offline  
post #7 of 16 (permalink) Old Jul 19th, 10, 11:11 AM Thread Starter
Tech Team
Bri
 
Join Date: Apr 2007
Location: ma
Posts: 69
Re: Rod too long ? Brakes locked up

After doing a lot more searching and reading through these posts, i am left to believe that there could be two possible causes of sustained fluid pressure to all 4 brakes ( which has to be the case since i never touch the back brakes and they had sever drag and smoked just as the front ones which i did replace). I know that i am using the correct lower pedal hole.
After completing the brake conversion i noticed that it was strange that i could not press the brake pedal to the floor or even close to it. I would get about a 1/3 a push and then it felt as if the brake pedal was pushing up against something rigid like metal and would go no further.

A. When i replaced the booster and MC, i arbitrarily set the clevis lenghth ( i just turned it and turned it until i could get all the parts to fit: Booster to clevis to pedal). Perhaps unscrewed it too far ( making the rod too long) so that in effect the brakes were on almost all the time. Then if the brake fluid heated up from excessive drag, it expanded putting more pressure on the brakes.

B. I am using the short rod with the adapter/receiver in the MC. Maybe the combined length of the long rod without the adapter in the MC is actually shorter than the short rod and the adapter thing in the MC. Perhaps i need to switch from short rod and adapter to long rod and no adapter.

Because i am an amature and because i bought the MC and booster in a kit with two rods etc, i believe that i am doing somehting wrong rather than having received the wrong or mismatched parts. Something is causing there to be sustained pressure in the brake lines....
plum_crazy_purple is offline  
post #8 of 16 (permalink) Old Jul 19th, 10, 12:12 PM
Moderator
Kevin
 
KevinW's Avatar
 
Join Date: Jul 2000
Location: Millstone, NJ
Posts: 11,001
Re: Rod too long ? Brakes locked up

Bri, When the booster is at rest the rod sticks out a set amount and the lower rod with clevis is only adjusted for pedal height. Nothing should be pressing on the MC. BUT if the rod sticks out too far from the booster at rest and you installed the MC, you would have had to use the nuts to tighten the gap. that is what puts pressure on the MC.

I would remove the nuts for the MC (you dont have to undo the lines, they have enough flex if you remove the lower clamp) and examine the rod and MC back. the difference between the rods in over an inch, so you should be able to see which MC you have. Luck!

BTW, the repro MC comes with both rods. And did you Bench bleed the MC before installing?

Kevin


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
KevinW is offline  
post #9 of 16 (permalink) Old Jul 20th, 10, 05:57 AM Thread Starter
Tech Team
Bri
 
Join Date: Apr 2007
Location: ma
Posts: 69
Re: Rod too long ? Brakes locked up

Thanks for your reply. Yes, I did bench bleed it the MC before installing.

I will try what you suggested. The kit came with a receiver of some sort ( a metal rod about an inch or two long that fits in the MC --- which is different than the two push rods that came with the kit. Perhaps this is what is causing the problem. I had been using it but perhaps i shouldn't be).

I really believe that because i was getting a "hard stop" when i pressed the brake pedal down only two inches ( as if it was hitting something metal), that i must have done something wrong with the rod.

Thanks again - I hope i can fix it and will get back as to what i found.
plum_crazy_purple is offline  
post #10 of 16 (permalink) Old Jul 20th, 10, 06:18 AM
Moderator
Kevin
 
KevinW's Avatar
 
Join Date: Jul 2000
Location: Millstone, NJ
Posts: 11,001
Re: Rod too long ? Brakes locked up

Luck, take some pics of the parts when you get it apart, so we can comment

Kevin


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
KevinW is offline  
post #11 of 16 (permalink) Old Jul 20th, 10, 06:42 AM
Gold Lifetime Member
John
 
Join Date: Dec 2008
Location: Louisville, Ky.
Posts: 3,403
Re: Rod too long ? Brakes locked up

Here's a pict of the tool used to measure the rod gor the master cylinder.
J-34783-A Kent-Moore U.S.A. (stamped on tool) the center rod slides
back and forth, measure the depth od the M/C then how far the rod
stisks out should have a small clearance.
Attached Thumbnails
Click image for larger version

Name:	DSCF2322.jpg
Views:	76
Size:	60.8 KB
ID:	16860  
john68 is offline  
post #12 of 16 (permalink) Old Jul 20th, 10, 02:29 PM
Senior Tech
Steps
 
Join Date: Dec 2005
Location: New Zealand
Posts: 13,316
Re: Rod too long ? Brakes locked up

A set of calipars with measure just as well... a 1mm clearance is all that is needed.

My Spelling is not incorrect...it is creative

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Steptoe is offline  
post #13 of 16 (permalink) Old Jul 20th, 10, 06:13 PM Thread Starter
Tech Team
Bri
 
Join Date: Apr 2007
Location: ma
Posts: 69
Re: Rod too long ? Brakes locked up

so the idea is to make sure there is 1mm of clearance between the tip of the extending from the booster and the receptor thing in the mc. ( nobody ever seems to talk about the receptor thing that fits in the mc in these kits. in the kit that i have there is an inch-and-half to two inch receptor rod thingy that fits right in the MC that extends back to the back of the MC - - this is different than the rod that fits in the booster and reaches out to the MC).

i do appreciate the help,i know it sound as if i couldn't change a tire. I will take some pictures and post them.
plum_crazy_purple is offline  
post #14 of 16 (permalink) Old Jul 20th, 10, 08:22 PM
Senior Tech
Wes
 
Join Date: Dec 2003
Location: Leander, TX
Posts: 2,758
Re: Rod too long ? Brakes locked up

If it's an aftermarket booster, you'll likely need to grind some length off the little push rod. I've used two of those repo boosters, and they work and look fine, but both needed adjustments (grinding) to the little rod; usually about 3/16".

Also, has the master sat, with fluid in it, for a long period of time? They can lock up.

Laslty, are you sure your pedal linkage is correctly installed and has the needed room?

Since all 4 corners locked up, you're looking in the right place; from the pedal to the master.

FWIW
Straight-line-69 is offline  
post #15 of 16 (permalink) Old Jul 26th, 10, 09:52 AM Thread Starter
Tech Team
Bri
 
Join Date: Apr 2007
Location: ma
Posts: 69
Re: Rod too long ? Brakes locked up

I compared the old MC rod length to the one i am currently using and they were the exact same length. I think what might have been happening is that the other rod, the one that goes from the pedal to the Booster was too long and then when i tightened the booster to the firewall it made it so that there was constant pressure on the brakes ( still not sure though because the problem didn't start until about 3 driving days after installing the disc upgrade). The new and the old MC looked exactly the same to me ( when i bought the car it had power drums on all 4).

This weekend i re-installed the old booster ( the one with the shortened pedal rod) thinking that it they looked exactly the same why not install the old one with the shortened pedal rod instead of cutting the pedal rod on my new booster. The results were disappointing. After bleeding the brakes again, its not working correctly. There is way too much play in the pedal now and i can get the pedal down the floor and it can't stop the car in a reasonable amount of distance. It also pulls to the left.

Because the rear drums are toast, i was going to replace them to eliminate that as a potential cause of my problems.

When i hit the brakes the nose does dive telling me that the front brakes are doing work so i don't think the proortioning valve is set wrong.

Am i correct in saying that if the brakes are correctly bled and the MC has been bench-bled, and if there are no leaks, that if i can press the pedal to the floor, the Booster pedal rod is incorrectly adjusted ? ( because brake fluid doesn't compress). There is about 3 inches of travel when i press the brake pedal before i feel any real type of resistance. I think this may be my problem.
plum_crazy_purple is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Team Camaro Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address.
NOTE we receive a lot of registrations with bad email addresses. IF you do not receive your confirmation email you will not be able to post. contact support and we will try and help.
Be sure you enter a valid email address and check your spam folder as well.



Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome