Kestrel Posted October 24, 2021 Share Posted October 24, 2021 Heading back from a pleasant drive today I noticed a smell like burning insulation. I found the left rear wheel was very hot and very hard to turn, almost impossible to rotate while off the ground on my lift. The odor was quite noticeable about a mile from home and still lingers in the barn. The E brake was not mistakenly left on. Any ideas on what to expect when I pull the brake drum tomorrow ? Frozen brake shoes, burnt wheel bearing ? New shoes and inner and outer bearings were replaced less than a 1000 miles ago. Thanks guys ! Link to comment Share on other sites More sharing options...
EmTee Posted October 24, 2021 Share Posted October 24, 2021 My first suspect would be a leaking axle seal that has allowed the differential lube to contaminate the brake linings. That causes the brake shoe to grab/drag and the heat generated exacerbates the situation. Everything may seem fine when the car first starts off. The smell is a combination of burnt oil and brake material. Look for evidence of oil leaking between the bottom on the drum and backing plate. Another possibility is failure of some piece of brake hardware (e.g., return spring or shoe retainer) that is allowing the shoe to contact the drum and drag. I once had the bonded friction material pop loose from a shoe on a rear brake. That caused the wheel to lock-up when moving forward, but it would release when backing-up... 2 Link to comment Share on other sites More sharing options...
avgwarhawk Posted October 24, 2021 Share Posted October 24, 2021 Brake shoes not returning after applying the brakes. Link to comment Share on other sites More sharing options...
packick Posted October 25, 2021 Share Posted October 25, 2021 My vote is with EmTee. I had the same thing happen to me with my '55 Century. The wheel seal failed and fluid leaked down on the brakes causing the smell and heat you mentioned. Upon inspection, the brake mechanism was OK, but I did have to replace the brake lining. I pulled the axle out, replaced the seal, and all was good from then on. Since I had everything apart, I also replaced the seal on the other side too. It was only a matter of time before that failed too. Link to comment Share on other sites More sharing options...
EmTee Posted October 25, 2021 Share Posted October 25, 2021 I agree with packick - if you find a leaking axle seal I recommend doing both sides. It doesn't take much more effort and you're better off dealing with it once, while you have all of the tools out. Depending upon the amount of contamination, you may be able to save the shoes. If they're not too badly soaked I have successfully washed them with brake cleaner and clean paper towels. Wash them until you don't get any color on the paper towel and let them dry. Lastly, scuff them off with some sandpaper to remove any surface glaze. 1 Link to comment Share on other sites More sharing options...
Kestrel Posted October 25, 2021 Author Share Posted October 25, 2021 Appreciate the advice ! Both sides, inner (w/new races) and outer seals were replaced and repacked in 2019. I didn't see any oil residue on the drum or backing plate, but it was getting dark. Maybe I installed the seals wrong. I'll know more tomorrow. I'd be happy with a broken spring or something obvious in the shoe mechanism. Link to comment Share on other sites More sharing options...
avgwarhawk Posted October 25, 2021 Share Posted October 25, 2021 Could simply be over adjusted and dragging the drum or the safety brake cable frozen not allowing the shoes to return. Link to comment Share on other sites More sharing options...
meteor Posted October 25, 2021 Share Posted October 25, 2021 Had the same issue with my 40 Special. It was the rubber brake hose to the rear wheel. Brake fluid would pass through but not return and kept the shoe from retracting. 1 Link to comment Share on other sites More sharing options...
old-tank Posted October 25, 2021 Share Posted October 25, 2021 2 hours ago, meteor said: Had the same issue with my 40 Special. It was the rubber brake hose to the rear wheel. Brake fluid would pass through but not return and kept the shoe from retracting. Go ahead and pull a brake drum to be sure you don't have a mess in there, then consider the rear brake hose. Another possibility is the residual pressure valve in master cylinder retaining too much pressure especially if exhaust components are in contact with any brake line. Link to comment Share on other sites More sharing options...
Frank DuVal Posted October 25, 2021 Share Posted October 25, 2021 If no grease seen leaking, then bad flex brake hose or DOT 3 froze the wheel cylinder. Wait, this isn't a Corvair with 4 brake hose, one for each wheel. So when the rear hose goes bad (to the rear axle), usually both rear wheels get hot. Link to comment Share on other sites More sharing options...
Kestrel Posted October 25, 2021 Author Share Posted October 25, 2021 Okay, getting there.. The drum rotated normally and I pulled it off easily but only after I backed off the adjusting star. The drum was seized up tight before I backed off the star. Maybe I had them adjusted too tight from the get go and for some reason, the shoes didn't retract when I let my foot off the pedal. I did adjust them all higher than the book called for. The book says to back off 6 "stars" worth. I didn't. The pedal seemed too low with 6 off. So I set all wheels only 2 or 3 beyond the dragging "feel". That gave me a nice high pedal. Maybe GM brake engineers know something I don't and the shoes just got stuck there ? Dunno.... Linings look okay but still stink. Cylinder moves in and out when pedal pushed. No leaks anywhere. Old Tank= Things are hotter at leaf rear with muffler right next to that wheel. Maybe that contributed to this ? Link to comment Share on other sites More sharing options...
JohnD1956 Posted October 25, 2021 Share Posted October 25, 2021 The cross bar in this picture is out of place 52 minutes ago, Kestrel said: 5 Link to comment Share on other sites More sharing options...
old-tank Posted October 25, 2021 Share Posted October 25, 2021 53 minutes ago, Kestrel said: Things are hotter at leaf rear with muffler right next to that wheel. Maybe that contributed to this ? Probably not. it would take direct contact. Years ago I went to rescue a friend with my 51 F-1 truck (3400 lbs) with a 2000 lbs trailer with a 74 Olds 88 (4800 lbs)...this put a brake hose tight against the exhaust pipe. I made it about a mile until it locked up. jacked up the rear wheels would not turn. While opening a bleeder I noticed the hose/pipe contact. 7 minutes ago, JohnD1956 said: The cross bar in this picture is out of place Good catch John! Link to comment Share on other sites More sharing options...
avgwarhawk Posted October 25, 2021 Share Posted October 25, 2021 (edited) Are these the correct shoes? The wheel cylinder shoe actuators are not horizontal. Edited October 25, 2021 by avgwarhawk (see edit history) Link to comment Share on other sites More sharing options...
Kestrel Posted October 25, 2021 Author Share Posted October 25, 2021 Yep, I just saw the slipped E brake cross bar and is now correctly back in its notch. Thanks ! Shoes are original as far as I know. I installed after market wheel cylinders. Actuators look a little off, I agree. Thoughts on any risk if they're not perfectly horizontal ? No leaks, expand fine, nice and dry. Maybe they square up after adjustment ? Wishful thinking ? There's about 500 miles on all brake parts, new lines as well. Link to comment Share on other sites More sharing options...
packick Posted October 25, 2021 Share Posted October 25, 2021 And remember. You can possibly raise the brake pedal height by adjusting the rod length that goes into the Master Cylinder. Link to comment Share on other sites More sharing options...
Kestrel Posted October 25, 2021 Author Share Posted October 25, 2021 Good tip. Thanks. I misquoted the shop manual earlier. The manual calls for backing off 15 turns of the star adjuster. Not 6 as I said. Either way I backed off enough so the tire spins freely. I checked the other side for the same adjustment. Now I should be good for a road test. When I centralized the shoes, the cylinder actuators looked more horizontal. I'm thinking perhaps that detached E brake cross bar somehow jammed the brake shoe tight against the drum when it fell out of its notch somehow or maybe I didn't re-assemble the mechanism properly 2 years ago. The lining was a little glazed in that section. I cleaned them up and lightly scuffed them. 2 Link to comment Share on other sites More sharing options...
EmTee Posted October 26, 2021 Share Posted October 26, 2021 It looks to me as though you may need to adjust the pin at the top that the springs are attached to. That pin adjusts up/down to get the shoes concentric with the drum. The picture looks like the pin is set too low. The gap between the top of the shoes and the edge of the backing plate looks larger than the similar gap at the bottom of the shoes. Link to comment Share on other sites More sharing options...
Kestrel Posted October 26, 2021 Author Share Posted October 26, 2021 Thanks Emtee. I just read the chapter that describes how to accomplish what you suggested. I give it a go tomorrow. The manual shows Special tool "J 854" anchor pin nut wrench. I think a 3/4 or 7/8" , etc. wrench will suffice. 😀 Link to comment Share on other sites More sharing options...
EmTee Posted October 26, 2021 Share Posted October 26, 2021 11 hours ago, Kestrel said: I think a 3/4 or 7/8" , etc. wrench will suffice. I agree -- the 'anchor pin' adjustment is what I was talking about. In my '38 shop manual it's covered in the 'major brake adjustment' section. 'Minor adjustment' is basically the shoe adjuster/expander adjustment that you performed previously. Link to comment Share on other sites More sharing options...
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