Upgrade front drum to disc brakes
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Upgrade front drum to disc brakes
Hi guys
I am about to upgrade my 1974 standard Bug front drum brakes to disc by swapping my front end with a 1500 type with discs that I have. Here in Oz the 1968 - 1970 SP1500s had disc front brakes but 1971 to about 1974/5 standard bugs (DP1300) had drums on the front.
My question is do I also have to change the master cylinder? Are they the same master cylinder ie is there a different dual type MC for drums v disc on front? Something I read in the Bentley suggested there is a difference.
Thanks in advance...
I am about to upgrade my 1974 standard Bug front drum brakes to disc by swapping my front end with a 1500 type with discs that I have. Here in Oz the 1968 - 1970 SP1500s had disc front brakes but 1971 to about 1974/5 standard bugs (DP1300) had drums on the front.
My question is do I also have to change the master cylinder? Are they the same master cylinder ie is there a different dual type MC for drums v disc on front? Something I read in the Bentley suggested there is a difference.
Thanks in advance...
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Thanks Bruce
My guess is that this car (good shape) has at least 500,000+ km on it. This is not huge mileage for a Beetle in Oz although hard to tell with these 5 digit speedos.
Bentley states that the MC for 1973+ models with 4 wheel drums are marked with a countersink in the mounting flange adjacent to the boss for the supply line from reservoir. I'm not 100% sure what is meant by a countersink in the mounting flange but I reckon I should be able to work it out.
Thanks again for your info about the replacement MCs...
My guess is that this car (good shape) has at least 500,000+ km on it. This is not huge mileage for a Beetle in Oz although hard to tell with these 5 digit speedos.
Bentley states that the MC for 1973+ models with 4 wheel drums are marked with a countersink in the mounting flange adjacent to the boss for the supply line from reservoir. I'm not 100% sure what is meant by a countersink in the mounting flange but I reckon I should be able to work it out.
Thanks again for your info about the replacement MCs...
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I have done it, it's pretty simple.
Get a new master cylinder, a 'general purpose' one. I don't think there are too many to choose from these days.
I recommend it just because it's nice to have a NEW one when you are redoing your brakes.
You need to keep the rear drums adjusted REAL tight, because with the disc conversion up front, teh brake balance shifts towards the front. You would be locking up teh front tires before the rear starts to brake properly.
You could fit type 3 brakes in the rear, or try reusing your old FRONT wheel cylinders in place of th rear wheel cylinders. The front drum brake wheel cylinders are bigger than the rear.
Jan
Get a new master cylinder, a 'general purpose' one. I don't think there are too many to choose from these days.
I recommend it just because it's nice to have a NEW one when you are redoing your brakes.
You need to keep the rear drums adjusted REAL tight, because with the disc conversion up front, teh brake balance shifts towards the front. You would be locking up teh front tires before the rear starts to brake properly.
You could fit type 3 brakes in the rear, or try reusing your old FRONT wheel cylinders in place of th rear wheel cylinders. The front drum brake wheel cylinders are bigger than the rear.
Jan
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Early dual-circuit M/Cs had discrete residual-pressure check valves which screwed into the M/C body (straight thread with copper gasket) and then the brakelines screwed into them. You don't want to run resid valves on the front circuit, that would make the pads drag and wear prematurely. I don't know what style M/Cs were used on the RHD cars in Australia, but if you have one with resid valves they can't be omittted since they also serve as thread adapters - but you can gut the two for the front brakes. Like Jan says, though, you probably don't have that setup and if you do it's probably due for replacement anyway.
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Bruce, Jan and Mark,
thanks heaps for your your input.
Jan I might go with your suggestion re: new MC. A friend said he can sell me German ATE MCs for about AUS$180 (about US$170). Not too bad a price. As one of the most important safety features on a car I wont compromise on this as I drive my kids in it. Car does about 200km a week so I need it to be reliable. I'll also replace the flexible brake lines.
One question for Jan re your comment:
You need to keep the rear drums adjusted REAL tight, because with the disc conversion up front, teh brake balance shifts towards the front. You would be locking up teh front tires before the rear starts to brake properly.
Presuming all was equal in Oz & US, by putting an early disc brake front end (1968-70) on my 1974 standard, wouldnt it make the braking system identical to the 1500 disc/drum set up? I thought the rear drums were the same on the 1500s as the 1974 standard?
I remember one of my ovals had a 1500 chassis with type 3 rears and these worked well without rear bias lock up.
Thanks again guys
PS: My friend suggested that while changing the front end I should throw in a set of caster shims (and longer bolts for them) even though the front end is not lowered. Are all of these shims equal out there? Any brands that should be avoided?
thanks heaps for your your input.
Jan I might go with your suggestion re: new MC. A friend said he can sell me German ATE MCs for about AUS$180 (about US$170). Not too bad a price. As one of the most important safety features on a car I wont compromise on this as I drive my kids in it. Car does about 200km a week so I need it to be reliable. I'll also replace the flexible brake lines.
One question for Jan re your comment:
You need to keep the rear drums adjusted REAL tight, because with the disc conversion up front, teh brake balance shifts towards the front. You would be locking up teh front tires before the rear starts to brake properly.
Presuming all was equal in Oz & US, by putting an early disc brake front end (1968-70) on my 1974 standard, wouldnt it make the braking system identical to the 1500 disc/drum set up? I thought the rear drums were the same on the 1500s as the 1974 standard?
I remember one of my ovals had a 1500 chassis with type 3 rears and these worked well without rear bias lock up.
Thanks again guys
PS: My friend suggested that while changing the front end I should throw in a set of caster shims (and longer bolts for them) even though the front end is not lowered. Are all of these shims equal out there? Any brands that should be avoided?
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Yes, you will be making the brake "bias" just like it is on the Beetles with factory front discs - and IMO that's not a good thing, particularly if you drive much on slick roads...the fronts will be more prone to premature lockup in a panic stop. I agree with Jan, hang onto the front wheel cylinders - you may want to use them on the rear if you experience this problem.
For a LHD Standard the "universal" M/C is a 113 611 015BD, available for considerably less - but they won't work on the right side of the tunnel without significant alterations. Time was, I was a real stickler for using only German Ate or FAG brake hydraulics, but it seems that their quality is no longer sufficiently better to justify paying 2 to 3 times as much as for the Brazilian TRW. There's also a couple of other German brands making reproductions (Brax and FRE) which are supposedly good-quality...I haven't used either yet so I don't have an opinion.
For a LHD Standard the "universal" M/C is a 113 611 015BD, available for considerably less - but they won't work on the right side of the tunnel without significant alterations. Time was, I was a real stickler for using only German Ate or FAG brake hydraulics, but it seems that their quality is no longer sufficiently better to justify paying 2 to 3 times as much as for the Brazilian TRW. There's also a couple of other German brands making reproductions (Brax and FRE) which are supposedly good-quality...I haven't used either yet so I don't have an opinion.
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Gonna Do Disc Brakes!
I am going to install dropped spindles and go with disc brakes on my 72 beam......Before I order the Brake Kit which comes with the dropped spindles, CIP1 needs to know if I want 4 lug rotors or 5 lugs. I would like some opinions on both before I order......could it be wheel options, safety, spacing, etc....
Thanks!
Thanks!
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Re: Gonna Do Disc Brakes!
From my perspective, you can narrow the argument down to what wheels do you want to run. You can opt for the stock 4 bolt, a 100 mm 4 bolt (Honda), a Porsche 5 bolt, or a Chevy 5 bolt pattern. Spacing will be a function of the rim chosen as various are availabe in each bolt pattern. Even custom wheels (I mean specific built, not just "aftermarket") are available for each pattern. Safety shouldn't be an issue at all; if it is, you should stick with oem parts.Lew wrote:I am going to install dropped spindles and go with disc brakes on my 72 beam......Before I order the Brake Kit which comes with the dropped spindles, CIP1 needs to know if I want 4 lug rotors or 5 lugs. I would like some opinions on both before I order......could it be wheel options, safety, spacing, etc....
Thanks!
So? What wheels do you like?
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First, thanks for your reply. I like these wheels and also like the wheels called "Flat Fours"! I wish I could see some other examples of wheels that could be an option.......As for my Car I am trying to accomplish the CAL LOOK Vehicle..... You may have seen in the TYPE 1 FORUM what I have been doing.....It's posted as "MY 72 BUG".
Thanks Again!
Lew
Thanks Again!
Lew
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- Lew
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I had a discussion with Marc, and now I might not order a Disc Brake Kit......I like the idea of the purchasing the dropped spindles seperate, and getting some good quality calipers that you can get replacement parts if needed.....Some of the kits I understand have calipers that you cannot get parts for......Right now, CIP1 has the ball joint dropped spindles for disc brakes for $129 with free shipping.....That's a very good price....Disc Brake Kits come with all the parts needed....So, bearings, seals, etc. would be an issue if Rotors, and Calipers were purchased seperately. I don't know what Calipers would cost, but if anyone would like to comment about my thoughts, or what you have done on your car, regarding disc brakes/dropped spindles, please let me know..... Any discussion, or advise is appreciated......
Regarding 4 lug or 5 lug rotors, buying the items seperately gives me more time to decide on the wheels I want to run.....
Regarding 4 lug or 5 lug rotors, buying the items seperately gives me more time to decide on the wheels I want to run.....
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If you'll be staying with the stock 4x130 lug pattern, these rotors will work:
http://www2.cip1.com/ProductDetails.asp ... %2D583%2DA
Brazilian-made TRW or Varga brand calipers have rebuild parts available; CIP1 has those too (for $8.50 ea more than the Chinese ones included in their kits):
http://www2.cip1.com/ProductDetails.asp ... 2D107%2D8A
http://www2.cip1.com/ProductDetails.asp ... %2D583%2DA
Brazilian-made TRW or Varga brand calipers have rebuild parts available; CIP1 has those too (for $8.50 ea more than the Chinese ones included in their kits):
http://www2.cip1.com/ProductDetails.asp ... 2D107%2D8A