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HT Brake booster / master cylinder
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How do you tell if a brake booster is from a HK/T/G or something later? Also can a master cylinder from a 6 cylinder HG be used on a brake booster (ie. for a V8 with disc brake front) or are there only certain master cylinders you can use with a brake booster? I apparently have a big nut master cylinder from a HQ (and on vehicle) but can I still use the this on a HT or do you I need to modify anything? Also what is the difference between a "big nut" master cylinder and an ordinary one? Heaps of questions but thanks for your help. |
Alex |
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OK.
First of all, there is no difference between a 6-cyl & a V8 m/cyl in a disc braked HK/T/G Holden (or any Holden series for that matter). With the exception of the rare 350 GTS m/cyl there are really only 2 types: disc brake & drum brake. Even then the difference is only minor. A 5 minute mod will change one to the other.
The 'big nut' description has a very simple explanation. All of the original (factory-fitted) master cyls had a cast iron housing & a large hexagon headed plug at the front. Virtually all aftermarket replacements have an alloy housing & no hex nut on the front.
When it comes to brakes you are better off going to a brake specialist (of the old school variety) & showing him what you have & he will tell you what you need. There are many 'traps' like depth of push-rod hole & different booster types, so don't be afraid to ask the questions.
If you need any more info, ask here on Fastlane.
Dr Terry |
If at first you don't succeed, just call it Version 1.0 |
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Thanks Dr Terry. When it comes time to sorting out the brakes I will definitely be getting expert assistance - at present I am just trying to sort out what I have, what I need and what I can dispose of. Is there any markings on the master cylinder or brake booster to give an idea of when they were produced (ie like steering boxes)? Also is there any way of telling the difference between the V8 and 6 cylinder master cylinders (for a novice like me and just by looking at them)? Cheers. |
Alex |
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There is no difference between the 6 and v8 master cylinders
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and the 350 one is so rare that you are unlikely to come across one. it is slightly taller but apart from that I think it looks the same
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Sorry my mistake. I meant the difference between the disc brake and drum brake master cylinders (not the V8 and 6 cylinder). |
Alex |
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The only difference between disc & drum brake master cyls is the presence (or lack of) the residual pressure valve in the outlet fitting for the front brakes. This can be fitted (or removed) at overhaul. Either cylinder can be used.
The best way to ID the brake booster is to look for the 'VH' number stamped into the housing. All PBR Mastervac boosters have this number.
Dr Terry |
If at first you don't succeed, just call it Version 1.0 |
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quote:
Originally posted by ht307munro
- at present I am just trying to sort out what I have, what I need and what I can dispose of.
A word to the wise, never dispose of anything no matter how stuffed or useless it is until the resto is finished.
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Thanks guys. I will look for the "VH" numbers tomorrow as I would like to keep it farely standard if possible, although would it matter if I used the later model big nut master cylinder with an older brake booster? Cheers. |
Alex |
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No, that's OK, the HQ/HJ one with the 'squarer' shaped body still looks better than an alloy cased aftermarket one. Just get rid of the red paint & paint it black.
Dr Terry |
If at first you don't succeed, just call it Version 1.0 |
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Just checked the master cylinders and boosters - hopefully someone can help interpreting these numbers. Big Nut master cylinder 7B7P and the word disc on the nut. One brake booster has a small tag on it with made under licence to Bendix Corp USA model no. 1WH305 (and also made in Australia on it). I can't find anything on the other booster. The second master cylinder has 26K8 and P66120 on the end of it. Any help appreciated. |
Alex |
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HT Brake booster / master cylinder
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