Hi Guys,
I have a question to why my Beetle pulls to the left when I use the brakes. Last year I installed a front disc brake kit on my 1968 Beetle from TRW. As well all the lines where blead and the rear drums were readjusted.
Does anyone have any ideas why my Beetle pulls to the left when braking?
Thanks
Brakes---Pulling to the left
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Marc
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We'll assume you've ruled out a tire pull (checked the pressures, tried swapping the front tires L<->R) and that you're talking about a distinct steering pull that you feel directly in the wheel, not a more-subtle drift that could be caused by a rear brake problem.
The usual suspects are a sticking caliper or a bad flex hose on one side. It's also possible that there's play in the suspension (a sloppy ball joint, or a bad control-arm bearing or bushing in the beam) that makes the alignment change on braking.
The FIRST thing I would check, though, is that you have the correct inner wheel bearings. `67/early`68 spindles took a smaller-I.D. inner bearing (and seal) than late`68-up spindles. The size of the tierod ends was changed at the same time, so if your outer tierod nuts are both 19mm wrench size it's safe to assume you have the right bearings - BUT if the tierod end end nuts take a 17mm wrench, you have the early spindles and if the inner wheel bearings are "late" they have ~1mm of slop, which can raise havoc with the brake action.
The usual suspects are a sticking caliper or a bad flex hose on one side. It's also possible that there's play in the suspension (a sloppy ball joint, or a bad control-arm bearing or bushing in the beam) that makes the alignment change on braking.
The FIRST thing I would check, though, is that you have the correct inner wheel bearings. `67/early`68 spindles took a smaller-I.D. inner bearing (and seal) than late`68-up spindles. The size of the tierod ends was changed at the same time, so if your outer tierod nuts are both 19mm wrench size it's safe to assume you have the right bearings - BUT if the tierod end end nuts take a 17mm wrench, you have the early spindles and if the inner wheel bearings are "late" they have ~1mm of slop, which can raise havoc with the brake action.
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VW&MGman
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Hi Marc,
Thanks for the reply and suggestions. I’ve verified the tire pressure, and last year when I installed the disc brake kit, I also installed new bearings, tie rod ends, and a new narrowed beam.
But even before I converted the front brakes to discs, the car pulled to the left. So as you suggest, it might be the rear brakes. Could the left (drivers side) rear brake cylinder be causing be subtle drift? I’ve verified and readjusted the rear brakes.
Thanks again
Thanks for the reply and suggestions. I’ve verified the tire pressure, and last year when I installed the disc brake kit, I also installed new bearings, tie rod ends, and a new narrowed beam.
But even before I converted the front brakes to discs, the car pulled to the left. So as you suggest, it might be the rear brakes. Could the left (drivers side) rear brake cylinder be causing be subtle drift? I’ve verified and readjusted the rear brakes.
Thanks again
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Marc
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When you bleed the rears do you get a good solid stream from both sides? If so the flex hoses are probably not the problem, but you may have a sticking wheel cylinder. With the drum off it shouldn't take much hand pressure applied to the top of each shoe to make the wheel cylinder pistons shift position. Also check that the adjuster screws are all in right-side-up (so the taper in the slot matches that of the shoe frame's end) - an upside-down one will dig a notch into the shoe frame and it won't slide in operation, resulting in false adjustment and erratic action.
You didn't mention replacing the flex hoses up front, so they're still suspect - again, you should get a good squirt from each side when bleeding.
If it pulled with two different beams the control arm bearings & bushings probably aren't at fault...but are the balljoints OK, and are they pressed into the control arms correctly? (the little notches in the flanges of the ball joints need to point fore & aft, if they're not the ball joint will bind when it travels).
You didn't mention replacing the flex hoses up front, so they're still suspect - again, you should get a good squirt from each side when bleeding.
If it pulled with two different beams the control arm bearings & bushings probably aren't at fault...but are the balljoints OK, and are they pressed into the control arms correctly? (the little notches in the flanges of the ball joints need to point fore & aft, if they're not the ball joint will bind when it travels).
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Jadewombat
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Re: Brakes---Pulling to the left
You probably have a leaky wheel cylinder. Pull the rear drums off and inspect, if you don't see any fluid on the shoes, take a tiny screwdriver and peel back the rubber boots on the wheel cylinders. If they're wet inside, replace. Replace both as well, even if only one turns out to be bad.VW&MGman wrote:Hi Guys,
I have a question to why my Beetle pulls to the left when I use the brakes. Last year I installed a front disc brake kit on my 1968 Beetle from TRW. As well all the lines where blead and the rear drums were readjusted.
Does anyone have any ideas why my Beetle pulls to the left when braking?
Thanks
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Ol'fogasaurus
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- Joined: Mon Nov 13, 2006 10:17 pm
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Ol'fogasaurus
- Posts: 17881
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It is probably the same as the manual. 
When you think about it, the two brake shoes are a semi floating assembly. They anchor at the slave cylinder (fluid/floating anchor [no pun intended]) and adjusting star plus they use the two studs with springs to hold the shoes against the backing plate. When adjusting brakes the key is; when you start adjusting a corner (side), you tighten the shoes until the brake drum will not turn (locked up). When you lock the brakes up, it centers the shoes in the drums. When the (brake) shoes are locked/centered in the drum, then you can loosen up on the (star) adjusting nut until (when you rotate the drum) you can just hear the shoes scraping against the drum. This gives you the proper, minimum (air), gap between the shoes and drum. If you don't do this then one shoe could be sitting closer to the drum than the other making it so you have to push the pedal farther to get both shoes to make contact with the drum. If/when they do center themselves then you have one side of the car’s brakes making solid contact before the other side does ending up in a pull to one side. (
An overly simplified and detailed description, I hope I am not coming across as talking down to you. If so, no intent was meant)
The only other thing I can think of, that has not been mentioned, is that between applications of the brake, fluid could be seeping backward from one of the wheel cylinders back into the MC reservoir. (This can happen when the wheel cylinder is higher than the MC.) Some MCs have enough tolerance or wear in them that this can happen. If the MC is allowing the brake fluid to seep back into the reservoir, and the MC is OK, you may need to put a residual pressure valve between the Master Cylinder (MC) and the wheel cylinders. (Rule of thumb on residual pressure valves is: 2# for disc brakes, 10# for can/drum brakes). Mixing drums and discs could exacerbate (different air gaps needed) this but then you said you had this problem before you converted to discs in front.
When you think about it, the two brake shoes are a semi floating assembly. They anchor at the slave cylinder (fluid/floating anchor [no pun intended]) and adjusting star plus they use the two studs with springs to hold the shoes against the backing plate. When adjusting brakes the key is; when you start adjusting a corner (side), you tighten the shoes until the brake drum will not turn (locked up). When you lock the brakes up, it centers the shoes in the drums. When the (brake) shoes are locked/centered in the drum, then you can loosen up on the (star) adjusting nut until (when you rotate the drum) you can just hear the shoes scraping against the drum. This gives you the proper, minimum (air), gap between the shoes and drum. If you don't do this then one shoe could be sitting closer to the drum than the other making it so you have to push the pedal farther to get both shoes to make contact with the drum. If/when they do center themselves then you have one side of the car’s brakes making solid contact before the other side does ending up in a pull to one side. (
An overly simplified and detailed description, I hope I am not coming across as talking down to you. If so, no intent was meant)The only other thing I can think of, that has not been mentioned, is that between applications of the brake, fluid could be seeping backward from one of the wheel cylinders back into the MC reservoir. (This can happen when the wheel cylinder is higher than the MC.) Some MCs have enough tolerance or wear in them that this can happen. If the MC is allowing the brake fluid to seep back into the reservoir, and the MC is OK, you may need to put a residual pressure valve between the Master Cylinder (MC) and the wheel cylinders. (Rule of thumb on residual pressure valves is: 2# for disc brakes, 10# for can/drum brakes). Mixing drums and discs could exacerbate (different air gaps needed) this but then you said you had this problem before you converted to discs in front.
Lee
My opinion is worth slightly less than what you paid for it.
My opinion is worth slightly less than what you paid for it.
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VW&MGman
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- Joined: Wed Feb 27, 2008 6:12 pm
Hi Lee,
Very nice explanation. Please don't feel that you are talking down to me. I take this site as a means of learning more about our great little VW's.
I think you and Marc are on to something about the wheel cylinders. Unfortunately I didn't have time to investigate them further, but based on the age of the car, they are probably due.
Thank you once again.
Very nice explanation. Please don't feel that you are talking down to me. I take this site as a means of learning more about our great little VW's.
I think you and Marc are on to something about the wheel cylinders. Unfortunately I didn't have time to investigate them further, but based on the age of the car, they are probably due.
Thank you once again.