- This topic has 31 replies, 12 voices, and was last updated 12 years, 6 months ago by
.
-
Posts
-
It turns out that I have “manual” brakes, disc in the front and drums in the rear, but the stopping power is nowhere near what I would like in the new monster. With probably more than 283 horsepower in her, I need brakes that will bring her to a halt quickly. The current situation doesn’t do that for me.
So I ran her down to the nearest Just Brakes and on the lift, they pulled all four wheels for an inspection while I hung around snapping photos with my cell phone.
The first thing I notice while it’s going up, the shocks are all leaking. I’m told that I need a new Master Cylinder, and the fluid looks black and dirty. Did I get taken or is it true: there were two rubberized “pillows” or plungers in the master cylinder top that were said to indicate a pressure problem.
Recommendations include replacing calipers, and machining the metal parts, new pads that looked OK to me, in the rear. I’m certainly no brake expert, but I don’t want to be taken for a rube, either. I need better stopping power.
Has anyone heard of a brake assist?
You don’t have enough leg to push disk brakes without a booster. It looks like a doughnut on the firewall. The master cylinder is attached to the center of the booster. The booster uses vacuum to help you push on the pedal. When it fails you have manual brakes. Check the vacuum line to the booster before you condemn it.
I’m not a fan of resurfacing rotors. That removes the case hardened surface and causes them to wear faster.
Calipers: Are they sticking? Do they grip the rotors evenly on both front wheels? Are the piston seals leaking? Why do they need to be changed?
Brake shops like to replace everything. That reduces callbacks and liability. That’s why they offer “free” brake inspections. They can always find something that could be replaced.
Black fluid indicates water in the fluid. It usually comes from water vapor in the air. Brake fluid is extremely hypergolic and will turn color from the air when you open the cap. It should be changed periodically.
Disk brakes use pads. Drum brakes use shoes. You have pads at the front and shoes at the back.
What about the rear wheel cylinders? They are usually the first to leak.
Brakes are important. It is better to replace too many parts than too few. Do it once and you won’t have to do it again. Think of it as insurance.
The rear wheel cylinders looked fairly new, and so did the shoes, but the springs looked old and suggested replacing those. They recommended replacing the shoes anyway, because he said, they need to mate up with the new part that they push against.
The inspector said the rotors had signs of overheating on one and “crystallizing” on the other, therefor the idea to resurface them.
The calipers where covered in grease, so to my eye, it looked like they were leaking.
Would brake fluid turn dark immediately when the cover was lifted, or might I have a leak, allowing air into the fluid system?
They recommended replacing the master cylinder. He didn’t mention that I have a booster, but a friend had suggested adding one to that system, if I have the room. So now I don’t know if I have one or not. I left the car at the brake shop and told them I didn’t need it back quickly.
I’m not an expert on brakes. But I do know that you have to have the vacuum to the brake booster or you’re not going to be able to stop very quickly in an emergency. make sure the vacuum to the booster is good before you replace the master cylinder. Also, and just a thought, if your brake hoses are over 10 years old, now would be a good time to replace those. Over time the brake fluid causes the inner diameter to start swelling and eventually will close off the hose enough to make the car pull one way or the other. The brake hose is one part of the system that usually gets forgotten.
Allen Caron
VW based 53MGTD - "MoneyPenny"
"If one thing matters, everything matters" - from the book The ShackMinor disagreement on discs without a booster. My front engine has discs front and drums rear. I do not have a booster, nor do I have room for one, but the braking is very good. I have leg problems, and even with those problems I have no problem. My front end is Mustang 2, and maybe there is a difference with different brands. If the calipers aren’t sticking, and are working well I wouldn’t replace them without a good reason. Are the rotors within specs? I agree with replacing the rubber hoses.
Pick up a copy of “Street Rodder” magazine.
Mustang II front crossmembers are available. Large disc brake conversion kits for Mustang II spindles are also available. Brakes from a full size ’80’s Caprice should be big enough.
Bill Ascheman
Fiberfab Ford
Modified 5.0, 5sp., 4:11
Autocross & Hillclimb
"Drive Happy"My Chevette based BCW has front disc and rear drum brakes but no power booster.Also, it does not have room for one.Braking seems OK to me but I do have to exert more pressure on the pedal than is required on power brake equiped cars.
I appreciate a car with lots of power but IMHO ,a 283 is just too much power for these little cars.I don’t mean to be critical but it’s difficult to balance suspension and brakes with that much horsepower in a car of this type.I’m sure it can be done but it seems that the builder of this one gave all his attention to the power department without considering the other issues.
I have drums all around on my VW based Duchess….but will chime in on the disc brake issue anyway.
In 1970, Karmann Ghias switched to front disc brakes…no power booster.
A very common upgrade to VW Beetles and VW based kit cars is an upgrade to front discs while retaining the rear drums. There are conversion kits for rear discs as well. Those conversions are not boosted either.
I can’t imagine the situation would be any different for a front engine car. In fact, I believe for a given hydraulic pressure, discs are more efficient than drums and might even require less leg power. (Don’t beat me up if I’m wrong on that… I did say “might”
)What IS critical, especially for front disc/rear drum is an adjustable proportioning valve to balance the front and rear brakes. This is needed because of the differing efficiencies between discs and drums and beucase of the odd weight distribution on our little cars. VW powered TD replicas are very “rear heavy” likely in the 40/60 or 35/65 range. Front engine TD replicas have better weight distribution, but are likely nose heavy.
PMOSSBERG40828.4064236111
Paul Mossberg
Former Owner of a 1981 Classic Roadsters Ltd. Duchess (VW)
2005 Intermeccanica RoadsterIf you own a TDr and are not in the Registry, please go to https://tdreplica.com/forums/topic/mg-td-replica-registry/ and register (you need to copy and paste the link)
You can have the rotors cut once. Have them check the runout first. If they’re warped (not “crystalized,” not blue) then they’ll need to be turned to bring them back straight. If not, not.
Calipers. They’re all wet? Replace. Also the pads and the soft hoses.
Rears drums: replace the shoes, wheels cylinders, soft hoses and–what the hell?–springs too, ’cause they’re cheap. If there’s a star wheel adjuster replace that too. Turn the drum only if it is warped, out of round, which it won’t be, so don’t bother.
Master cylinder. Is it leaking? Then replace. Is it more than, say, 10 years old? If so, replace. You’re in it–so why not. New fluid for cars not driven much.
Brake booster: I’d say not. You’re not stopping 300 hp; you’re stopping 2200 pounds from 75 mph. It could have 10,000 horsepower or 25 hp, if the mass is one ton, it’ll stop the same.
I ran a ’67 Nova SS with a small block (300 hp, give or take 50), and did a front disk brake upgrade on it ’cause the drums tended to pull. Did not need a “proportioning valve” and did not install a brake booster, though I had room and considered doing it as a next step. Didn’t need. Once the brakes were done, I had plenty of pedal and the car stopped straight and true, and didn’t require an airstrip’s length of tarmac to do so. That car weighed about 2800 lbs. Your car weighs two fat guys less than that. So you should be fine with manual brakes.
Try it first. Upgrade as needed.
Paul, my Ghia has front discs and rear drums. Stops fine. But I don’t have an adjustable proportioning valve on her. Perhaps I need to add that. My TD Chassis is from a 71 Beetle donor with drums all around. How does your TD stop with full drums? Thinking of keeping the drums all around on mine.
Allen Caron
VW based 53MGTD - "MoneyPenny"
"If one thing matters, everything matters" - from the book The ShackMy guess for factory stock Ghia’s is that the system was designed and set at the factory, so owner adjustments are not needed.
I’ll defer to those with actual experience on the proportioning valve issue. I was relating info from some friends that have done this. But I did a quick look through various vendors that sell drum to disc conversion kist and none mention the proportioning valve. So I guess it’s not rquired. Still seems like a good idea to me tho.
I’ve been fine with all drums since 1983. Heck, they worked on stock Beetles for decades! But if I ever planned to do any serious track time, even just at club events, I would want at least front discs.
PMOSSBERG40828.5455208333
Paul Mossberg
Former Owner of a 1981 Classic Roadsters Ltd. Duchess (VW)
2005 Intermeccanica RoadsterIf you own a TDr and are not in the Registry, please go to https://tdreplica.com/forums/topic/mg-td-replica-registry/ and register (you need to copy and paste the link)
I would suggest brake fluid replacement and re-bleeding the brakes. Get that old fluid out of there and the air and see what you think about the brakes. Then re-evaluate, fluid replacement is cheap.
In a ford based car there isn’t room for a power booster. The donor car may or may not have had power brakes (1974?)
There is a brake pedal mod to lenghten the brake pedal to give it more of a mechanical advantage. Has the brake pedal arm been reworked for lenght? Has it been welded?
I’m going to have as much of the brake system replaced as possible. The certified brake specialist at the shop and I are talking the same language. If I have this car going 70 mph on the freeway and need to stop quickly, I need the entire system to work its best.
I’ll give a run down on all the work that is suggested once I hear from the shop. Right now they are trying to run down the parts for matching them up for replacement.
The previous owner was told that the rear end is a Nissan 260Z, but couldn’t confirm that, and didn’t know what the front end was from. All four wheels on the car are marked Nissan and are a four bolt pattern.
Might all be z stuff then and that was good for stopping z-cars. The early ones weighed about 2400 lbs. The later ones bloated up to about 3000.
Doubt you have a z front suspension since they were McPhearsons and there isn’t room for those on a TD.
Do let us know, and please post photos. I think we’re all pretty much living vicariously through you at this point, at least when it comes to interesting TD replicas.
Gee, it was not till the mid 70’s that power brakes were in most cars my 69 mustang did not have them it had a 302 , 225 hp and stopped when i needed it to. you may just need the system gone through ,the master cylinder if it is a chevy kit will all be the same from chevette to impala, Jeep had a power brakes that may fit it had a very small buster . you can also put in larger roters and and milti piston calipers on her, you are only limited by what you want to spend $$$$$$$$$$ good luck Dan
It’s not getting rotors turned, I’m getting new ones. In fact, I’m getting the whole system replaced. Rebuilt parts when new replacements are not available.
The front end is from an ’84 Chevette and the rear end is from a, ’86-’88 Nissan 240 ZX or maybe a 260Z. What a strange combination.
She was only stopping on one wheel, so the new brake job should make a big difference.
Keep in mind that if you’re using a brake master cylinder off a car that had previously had power brakes the master cylinder may not be appropiate. Master cylinders come in various bore sizes for different applications. Factors like weight of car, brake lever mechanical advantage and whether power brakes are incorporated are all factors.
Of course if only one wheel was working is certianly need for concern. Find a dirt road and do some testing to see how things are locking up.
One wheel eh? It sounds as if one circuit on your dual circuit master cylinder has failed. That happened on my Avanti. Scary.
Only one wheel braking could be bad brake lines too.
Paul Mossberg
Former Owner of a 1981 Classic Roadsters Ltd. Duchess (VW)
2005 Intermeccanica RoadsterIf you own a TDr and are not in the Registry, please go to https://tdreplica.com/forums/topic/mg-td-replica-registry/ and register (you need to copy and paste the link)
It’s getting a re-manufactured master cylinder, new brake lines, including one steel covered line that was getting rubbed due to the routing it has underneath running to the rear.New pistons, new shoes, new pads, new rotors, infact everything that can be replaced, I think, is being replaced.
I just got a call 35 minutes ago. The car is still at the brake shop. They told me the brakes are working,
but unbalanced, stopping more in the rear than the front. It has a
proportional device, but needs to be reset. They also said the builder
jury-rigged the wiring and they’re having trouble getting the brakes
lights to work properly.Under that dash, it’s a rats nest. I’m afraid to try to tackle it. The seller really misled me on this purchase. And, there is no under-dash cover, so the wiring just hangs free.
Whom ever said in a post above, that the seller thought more about getting power to the engine and not much about anything else gets my vote.
It’s sad that some people misrepresent the condition of what ever they are selling.What sounds good in the description and even looks good in the pictures ,often turns out to be completely different when the vehicle is delivered.
About the wireing under the dash,When the wires are properly routed and supported ,they will not need to be covered by a panel beneath the dash.They will be out of sight unless you are looking at them from a position almost directly under the dash[ as with your head actually beneath the dash.] My London Roadster came with a panel to cover the area behind the dash but I disgarded it and moved the wires up high enough that they are out of sight.I like to be able to get under there quickly without having to remove a panel to check a fuse etc.
Hope you get your car back soon . You need a pleasant ride for a change.
I’m towing the London Roadster, which is currently engine-less up to a fiberglass expert for an estimate on repairs that I don’t want to tackle. Its new block was delivered to the machine shop this morning for the valve enlargement job and rebuild, which I hope comes to conclusion this next week.
The hot rod is getting brakes and wiring figured out, so maybe it’s Honda S2000 time for this weekend’s fun.
The hot rod is back from the expensive brake job and I am NOT impressed. I don’t feel a lot of difference. The master cylinder could not be changed. It turns out there were maybe three different master cylinders for the Chevette (front end) and Just Brakes could not get the new one to work correctly. The told me I need to drive the car 250 to 500 miles for the brakes to “break in”. I’ve never heard of that.
I do have a proportioning valve and it is adjustable. The new front shocks are red, so they blend with the car color. The rear shocks were reported custom made and no off the shelf model is available. The wheels were balanced, so hopefully she will ride better now.
Wow. I don’t think I would accept that brake job. Not at that price.
250 miles for the brakes to “break in” is so bogus even Click & Clack would both yell “Booooooo-gussss” if you called them on their radio show. You should do that. Bet they take the call (Tommy has an original and apparently unrestored ’52 TD). They might even give good advice, though the chances of that are slim.
Meantime I’d start looking for a hot rod shop to help with this. Gotta be someone in Phoenix who knows how to build a brake system from random parts.
Mark I agree with Ed, break in time is BOGUS!!! The only time this might be (and thats a stretch in this case if they used all new parts) is if you had used the old rotors that had groves in them from worn out pads. If you leave the pads on long enough the rivets cut into the rotors or drums. If their too bad you replace them, if not they get turned.
There is an exception, back in the day, some racers cut groves in their rotors or drums and rode the break till new pads conformed to match them. This was for more surface area and faster breaking. There is a fine line of error here and they have to know what they are doing.
- You must be logged in to reply to this topic.