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Brakes, brakes, and more breaks

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Rut

Rut

Obi Wan
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When is a brake not a break or...
I need genuine thinking cap stuff on this one. It may be common, but it has me a little more befuddled than usual. I've rebuilt my brakes on my bugeye from the top down, new Tilton 3/4" 74 series MC, new hard lines, new braided flex lines, rebuilt by Peter C calipers, all new. In the back, new lines, same as the front, parking brake cleaned and greased up, old BE style drums, new cylinders and kits, shoes, and turned drums. Not too much difficulty in bleeding the system, but it never feels just right. On the rear it's difficult to get the drum off and on unless you manually push the driver side parking brake rod away from the wheel. On the passenger side, no problem at all. When I fired her up and put her in gear I noticed that the drums appear to be out of round. The lugs, hubs, and 2 screws that hold the drums on are going in a perfect circle, but the outside of the drums themselves are more than 1/4" out of round, both sides. When you press the brakes or pull up on the parking brake it 'feels' normal. 1, is this normal or common, and 2, should I ditch the bugeye rear brakes for a newer set up? I want a good performing system obviously, but would a new rear set up be easier than fooling with what I have? I can take the car out and put around the neighborhood, but the brakes are not awe inspiring in performance. Thoughts?
Thanks, Rut
 
Rut, IF there's any question about the fitness of your rear brake drums, you can purchase new ones for $30 (Moss). If I had <span style="text-decoration: underline">any</span> question about the drum being defective, I'd order new ones immediately and be done with it.

Regarding the parking brake thing (I have a MK III), I also have to fiddle with the parking brake to get the drum off. Unless the parking brake is sticking or frozen on the drum, this doesn't seem to be a problem. Maybe your parking brake needs adjustment (easy to do).

Seems that with your front Tilton setup, you'd be in good shape. The front brakes do most of the real work anyway.

Strange. Let us know what you decide, and good luck.
 
Mark, thanks for the reply. I think the drums are ok, but I have not measured them to make sure they are within spec. Do the newer style rear brakes use the same drums as the old BE style? I think I have a hydraulic problem, but the lines are good (new) and the PO said the rear cylinders were new. I do not know what size bore the 'new' rear cylinders are and I could have a miss matched set with the 3/4" MC, good front calipers, and ? rear cylinders. Thoughts?
Thanks, Rut
 
Rut, you do have a mismatched system. The stock BE master is 7/8 and you now have 3/4. The rear brake cylinders are changed in bore size as well when BMC went to the 3/4 master. Don't know if its all that big a deal since I'm sure there are many running the same set up as you. Off the top of my head I believe you would be getting more force on the rear shoes than the original disc brake design. Proportionaly. Whether that would make a difference in stopping distance or general performance I could'nt say.

Kurt.
 
nomad said:
Rut, you do have a mismatched system. The stock BE master is 7/8 and you now have 3/4. The rear brake cylinders are changed in bore size as well when BMC went to the 3/4 master.

Kurt.
Click to expand...

Correct, but here is your problem. The Tilton does not have a residual valve. I use the same MC when I convert Morris Minors from mechanical to hydraulic clutch system. You need a residual valve for the rear brake shoes to remain within range of your drums. If you notice that a pump or two on the pedal brings the pedal up, that's the reason (other than air in the system). Your best bet for a simple solution is to add a 10lb in-line residual valve to the rear brake line. I would recommend this even if you convert to the dial piston 3/4" rear wheel cylinders. In addition, you must make sure that your rear brakes are adjusted correctly and that you have right adjustment on your parking brake cable. 3 to 4 clicks should be all you need to lock up the rear brakes with the handbrake.

The other thing to examine is that the piston in one of the wheel cylinders is not frozen. You have a steel piston in an aluminum housing. You know what happens when you mix these two metals and water is involved. Also, you don't mention brand of wheel cylinders you replaced with, but I am always suspect of anything not original Lockheed in replacement parts.
 
Ah yes, Gerard! Not familiar with the Tilton but that makes perfect sense. I knew the valve in the back of the stock master was to keep some pressure on the system but never bothered to ponder why!!

Kurt.
 
Gerard, I have been in touch with Tilton about the 10 psi residual valve/spring and they are researching the issue. At first I/they thought it was not needed, then I mentioned the simple, single circuit of the Bugeye and they had to check. That said, I'm leaning toward the newer drum brakes with the dual piston cylinders and a name brand at that. I don't know what brand my PO put in, but it needs some help. From the info I've received I think that may be the source of my problems. I'll feel better if I start fresh with a system I'm comfortable with.
Thanks all, Rut
 
I'm not sure what there is to research. You have two very strong springs that retract the rear shoes, which returns fluid to the master cylinder. It's SOP to keep residual pressure on drums brakes, front or rear. Because of the proximity of the MC to the discs on a Morris, I use a 2 lb residual valve on the front discs too. If you were using the 3/4" disc brake MC I supply, there is a restrictor valve that is correct for the Bugeye DB conversion, but unless the Tilton is has the same provision, you will benefit from the in-line valve. I've done this on numerous DB conversions, and the difference is noticeable.
 
Gerard, I've been in touch with Tilton as I said earlier and I believe I'm the one who's confused. When I read your post regarding the 10 psi valve I thought you were referring to the one built into the MC. Tilton offers the 74 series both ways, with and without, so that's where my head was at. They cleared that up and mentioned adding the 10 psi valve on the rear line only and it comes from Wildwood and if I read your post correctly that's what you said. I have dual Tilton MCs, one for the brakes and one for the clutch and I'm also looking at adding an internal hydraulic throw out bearing. I've got the necessary parts to put it together and will have it installed with a remote bleeder. All in all I've found Tilton to be very responsive regarding the possible uses of their products and think I'd like to try this. Any additional thoughts?
Thanks, Rut
 
Rut said:
Gerard, I've been in touch with Tilton as I said earlier and I believe I'm the one who's confused. When I read your post regarding the 10 psi valve I thought you were referring to the one built into the MC. Tilton offers the 74 series both ways, with and without, so that's where my head was at. They cleared that up and mentioned adding the 10 psi valve on the rear line only and it comes from Wildwood and if I read your post correctly that's what you said. I have dual Tilton MCs, one for the brakes and one for the clutch and I'm also looking at adding an internal hydraulic throw out bearing. I've got the necessary parts to put it together and will have it installed with a remote bleeder. All in all I've found Tilton to be very responsive regarding the possible uses of their products and think I'd like to try this. Any additional thoughts?
Thanks, Rut
Click to expand...


I've had very good results with Tilton. I've only seen one (out of maybe 10 or 12) that was short lived and had to be replaced in a relatively short period of time.

Yes, Wilwood is the brand of residual valve I use and if you go back over the posts, it was the 10 psi one I use for the rear. You would use the 2 psi only for discs. If you have NO residual valve in your 3/4" 74 series, you might consider adding the 2 psi in front, but I'd say it's more optional than necessary than in the Morris. You would use a residual valve on the clutch side.
 
Gerard, thanks again for the info. I think I have what I need info wise to get this done and will follow up with the results.
Thanks, Rut
 
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