Remote servo - rebuild or let well alone?

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Beginning my winter's work on the Rambler, somewhat delayed by a lot of old-house stuff. 
One item is the servo. My Canadian export rhd car has an indirect servo and single line brakes.

The servo works fine. But as everything else in the system has been refreshed, it seemed logical that the servo might be needy. I assumed there are hydraulic pistons in there, after all there are bleed valves on the servo itself. So I was going to take it out and send it to a company that can recondition them.

Started the job yesterday. Unsurprisingly, the brake unions don't want to undo, and despite soaking with PlusGas I can see that the brake lines are likely to twist and shear off. 

So I look online to see how the servo works - never had one apart - and it appears as if all that's in there is an air valve and diaphragm. No hydraulics, no rubbers.

I never see threads on here about servos. Perhaps they just go on and on.
Should I just leave it alone?

What do you think?

Ivor

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990V8 Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Oct/07/2016 Location: Gloucestershire Status: Offline Points: 788	Post Options Post Reply Quote 990V8 Report Post Thanks(0) Quote Reply Topic: Remote servo - rebuild or let well alone? Posted: Feb/20/2019 at 4:06am
	Beginning my winter's work on the Rambler, somewhat delayed by a lot of old-house stuff. One item is the servo. My Canadian export rhd car has an indirect servo and single line brakes. The servo works fine. But as everything else in the system has been refreshed, it seemed logical that the servo might be needy. I assumed there are hydraulic pistons in there, after all there are bleed valves on the servo itself. So I was going to take it out and send it to a company that can recondition them. Started the job yesterday. Unsurprisingly, the brake unions don't want to undo, and despite soaking with PlusGas I can see that the brake lines are likely to twist and shear off. So I look online to see how the servo works - never had one apart - and it appears as if all that's in there is an air valve and diaphragm. No hydraulics, no rubbers. I never see threads on here about servos. Perhaps they just go on and on. Should I just leave it alone? What do you think? Ivor
	63 Canadian Ambo 990 V8 327 74 LandRover Lightweight V8 SIII Shopping Trolley

Buzzman72 Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Sep/15/2009 Location: Southern IN Status: Offline Points: 2725	Post Options Post Reply Quote Buzzman72 Report Post Thanks(0) Quote Reply Posted: Feb/20/2019 at 6:12am
	Google "Bendix Hydro Vac." There are places out there that rebuild them; I'd personally prefer to have an experienced pro rebuild it, especially if I don't have a manual for servicing it.
	Buzzman72...void where prohibited, your mileage may vary, objects in mirror may be closer than they appear, and alcohol may intensify any side effects.

6PakBee Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Charter Member Joined: Jul/01/2007 Location: North Dakota Status: Offline Points: 5457	Post Options Post Reply Quote 6PakBee Report Post Thanks(0) Quote Reply Posted: Feb/20/2019 at 9:27am
	My recommendation would be to get a complete rebuilt spare and put it on the shelf for the day you need it. OR, get a rebuildable unit, have a firm rebuild it, and then put it on the shelf. I attempted to rebuild one of these on an International Loadstar years ago and the lack of parts and instructions pretty much put that plan in the dumpster.
	Roger Gazur 1969 'B' Scheme SC/Rambler 1970 RWB 4-spd Machine 1970 Sonic Silver auto AMX All project cars. Forum Cockroach

farna Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Moderator Lost Dealership Project Joined: Jul/08/2007 Location: South Carolina Status: Offline Points: 19676	Post Options Post Reply Quote farna Report Post Thanks(0) Quote Reply Posted: Feb/21/2019 at 7:36am
	This might help: http://www.chevyc60.com/bendix_hydrovac_overhaul.htm There is a hydraulic servo in there! The standard brake master cylinder goes to the remote power brake unit and pushes a slave cylinder. The slave cylinder activates the master on the remote unit. The master and slave on the remote unit seem to be integrated, not two separate units. This will help also: https://techtalk.mpbrakes.com/boosters/remote-mounted-brake-boosters-vacuum-booster If you wanted to replace it and wasn't all that worried about 100% stock appearance, you could get one of the universal single diaphragm units from MP Brakes. It's similar to the original and would look right at home, just some minor differences.
	Frank Swygert

990V8 Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Oct/07/2016 Location: Gloucestershire Status: Offline Points: 788	Post Options Post Reply Quote 990V8 Report Post Thanks(0) Quote Reply Posted: Feb/21/2019 at 2:14pm
	Thankyou. Looks hard to find another unit the same. Even on eBay US, I see hardly anything, and then mostly not the remote variety. I guess I'd be looking in Australia or perhaps Canada. That MP Brakes unit might be OK, I see it's a 2:1 boost. I wonder what ratio the unit on my car is. Anyone know the boost ratio for the standard non-remote booster.... perhaps it's in the shop manual, I'll have a look tomorrow, logically mine should be the same. I can get 2:1 remotes over here in the UK for about £150 / $200. As you say, not that bothered about originality. I'll also ask Reman Corporation whether they have an exchange unit. Well, logically the hydraulic cylinders in the booster should be as shot as the rest of the system. I've had to replace the master and all four corners, but the booster goes on and on. Ivor Edited by 990V8 - Feb/21/2019 at 2:18pm
	63 Canadian Ambo 990 V8 327 74 LandRover Lightweight V8 SIII Shopping Trolley

rocklandrambler Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Feb/09/2013 Location: Nanuet, NY Status: Offline Points: 3953	Post Options Post Reply Quote rocklandrambler Report Post Thanks(0) Quote Reply Posted: Feb/21/2019 at 4:31pm
	I seem to recall a friend of mine once had a '54 Mercury with a remote power booster. Probably some of the other early Ford products used one.
	Past AMC's 1974 Hornet X (new) 1975 Gremlin X (new) 1964 Classic 660 Cross Country 1965 American 440-H

990V8 Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Oct/07/2016 Location: Gloucestershire Status: Offline Points: 788	Post Options Post Reply Quote 990V8 Report Post Thanks(0) Quote Reply Posted: Feb/22/2019 at 2:04pm
	Yes, they seem to have been quite common at one time. Looked in the 62 and 63 TSMs today, much information about how they work, how to repair them, but nothing about the multiplication ratio. Waiting to hear back from MP Brakes, and Past Parts in the UK. Ivor
	63 Canadian Ambo 990 V8 327 74 LandRover Lightweight V8 SIII Shopping Trolley

990V8 Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Oct/07/2016 Location: Gloucestershire Status: Offline Points: 788	Post Options Post Reply Quote 990V8 Report Post Thanks(0) Quote Reply Posted: Mar/03/2019 at 2:16pm
	Never heard from MP. Past Parts say no problem to refurb, so I took it out and off it went. Considering that it may never have been off the car, was amazed how the brake unions came undone without spinning the pipes. Well, I had soaked them in Plusgas for a few days, but even so...... Ivor
	63 Canadian Ambo 990 V8 327 74 LandRover Lightweight V8 SIII Shopping Trolley

990V8 Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Oct/07/2016 Location: Gloucestershire Status: Offline Points: 788	Post Options Post Reply Quote 990V8 Report Post Thanks(0) Quote Reply Posted: Apr/08/2019 at 12:45pm
	Got it back, all rebuilt and shiny. £310/$400. A note with it saying that on receipt it was giving no boost and had significant vacuum leaks. It worked on the car, but then the car has a 327ci vacuum pump. Was interested in the leaks comment; I've posted a couple of times about the car suddenly developing idle problems on a long journey. I'd put that down to bad fuel as a topup of fresh fuel cured it, but twice? And when I regularly fill up my other cars from the same petrol station with no trouble? So I'm wondering now if the idle issue was a leaking booster that only leaked when the engine bay was heatsoaked. The boost ratio, btw, is 2:1. Anyway, question: Never worked on a booster before that has bleed nipples. I bled the brakes today, but should I bleed the booster nipples again with the engine running or does it make no difference? Ivor
	63 Canadian Ambo 990 V8 327 74 LandRover Lightweight V8 SIII Shopping Trolley

6PakBee Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Charter Member Joined: Jul/01/2007 Location: North Dakota Status: Offline Points: 5457	Post Options Post Reply Quote 6PakBee Report Post Thanks(0) Quote Reply Posted: Apr/08/2019 at 3:56pm
	I am surprised your rebuilder didn't include bleeding instructions. The last time I did this the booster came with a card that listed the procedure. In any event, this should answer your questions on bleeding. The procedure is near the end. http://www.icta.club/wp-content/uploads/2015/08/Service-Bulletin-Brakes-Hydrovac-Unit-7-1-591211.pdf
	Roger Gazur 1969 'B' Scheme SC/Rambler 1970 RWB 4-spd Machine 1970 Sonic Silver auto AMX All project cars. Forum Cockroach