Mercedes 608d brake servo.

[WalterScott]

My Mercedes 608d van, 1986 model, requires the brake servo part no. A0014304630. Is there any help out there? One or two appear for sale online, only to be 'out of stock' when I attempt to purchase. Or could I find a repair kit? I have searched everywhere and am now stuck.

 

[carat 3.6]

Have you asked Mercedes themselves?

 

[WalterScott]

Have you asked Mercedes themselves?

Yip. Obsolete is their reply.

 

[WalterScott]

Companies like Pastparts, etc., won't take on the reconditioning of the unit unless I can find a repair kit, which I can't. Does anyone out there know of other servos that might work?

 

[DSM10000]

Companies like Pastparts, etc., won't take on the reconditioning of the unit unless I can find a repair kit, which I can't. Does anyone out there know of other servos that might work?

Is it a servo or vacuum pump?

 

[WalterScott]

Is it a servo or vacuum pump?

Servo ATE 3.6147-0501.4 or A0014304630

 

[WalterScott]

More pics. 9-inch diameter

 

[WalterScott]

The mechanic sprayed a little loosener in and pushed the rod a few times. This feels good; the pressure seems alright, as if the diaphragm is doing its job. I'm going to stick this back on. The problem is still there. At this point, it was noted that air was being drawn in from the breather tube. Servo back off.
When applying pressure to the brake pedal it is very stiff until a little more pressure is applied then whoosh, the pedal is sucked to the floor and the vehicle performs an emergency stop. Depending on what mood the pedal is in, it might slowly return to top position and release the brakes, but mostly the pedal has to be physically pulled back up and the brakes release.
I've had the master cylinder and wheel brake cylinders changed.

 

[carat 3.6]

Give these guys a ring: Welcome | Peter Bassett Ltd | Truck & Trailer Parts, Agri Spares, Tools & Consumables

If it is completely unobtainable I'd look into fitting the unit from a later sprinter.

 

[WalterScott]

Give these guys a ring: Welcome | Peter Bassett Ltd | Truck & Trailer Parts, Agri Spares, Tools & Consumables

If it is completely unobtainable I'd look into fitting the unit from a later sprinter.

I am attempting to learn about any other options available and looking for any helpful input. My servo is located under the van in an awkward position above the leaf springs. The servo has a 9 inch diameter which I would have to replace with something similar in size. Would a servo from a sprinter have enough vacuum, what strength of internal spring. Would my master cylinder attach or would I use a new servo and cylinder together? my master cylinder has, pressure reduction valves ( I think that's what they are called), they are fitted for a reason, does a sprinter servo and cylinder have this. What effect would a sprinter set up have on my brakes? I am just tryna feel my way forward here. Any input is more than welcome.

 

[colinallcars]

Give these guys a ring: Welcome | Peter Bassett Ltd | Truck & Trailer Parts, Agri Spares, Tools & Consumables

If it is completely unobtainable I'd look into fitting the unit from a later sprinter.

What about a generic, remote one?

 

[WalterScott]

What about a generic, remote one?

I am willing to investigate any possible solution. I don't have any knowledge of remote servos. My mechanic might, I'll put the idea to him and see what he thinks?

 

[carat 3.6]

Not exactly the same but this is on ebay: https://ebay.us/m/DXzgtg

 

[WalterScott]

Not exactly the same but this is on ebay: https://ebay.us/m/DXzgtg

That one has a larger diameter which doesn't work with the space I have. Thanks for looking though.

 

[Bellow]

When applying pressure to the brake pedal it is very stiff until a little more pressure is applied then whoosh, the pedal is sucked to the floor and the vehicle performs an emergency stop.

I think... there is a rubber spacer within the servo between pedal and diaphragm through which your pushing on the pedal is relayed to the diaphragm the purpose of which is to deform depending on pedal force and thus invoke the servo's assistance. 39 years would be ample time for it to perish, go rock solid, and be incapable of performing as it should.

Depending on what mood the pedal is in, it might slowly return to top position and release the brakes, but mostly the pedal has to be physically pulled back up and the brakes release.

Which puts me in mind of it being 'sticky' inside - despite the penetrant having loosened it enough to permit application - but not release. Possibly, the return spring is tired or broken.
The rubber widget (if I'm correct on that) and spring would require striping the servo to pursue - as would rebuilding with a repair kit. What is included in a repair kit? You seem not to have a leak - but maybe the widget is a replaceable part? (I'd open it up - little to lose and a chance that it's (simply) repairable).

my master cylinder has, pressure reduction valves ( I think that's what they are called), they are fitted for a reason, does a sprinter servo and cylinder have this.

I think... the likes of pressure reduction valves are no longer required when there's ABS. So long as they are on the MC not the servo, another servo should be fine.
Re alternative servos. Looks like what I'm very familiar with ie, from a distance there appears to be multiple possible replacements but when offered up myriad little differences prevent it being of use. Maybe, there's one out there that will slot right in... Otherwise remote servos should be more universal (re fitting) but as well as the correct(ish) chamber diameter, internal hydraulic cylinders may need to be studied - only 'may' though. A remote servo would leave the problem of what to do with the existing servo given it sits between pedal and MC. (Gutting it but for the pushrod?)
As a last resort there's HydroBoost which is a non-vacuum assistance system that uses the power steering pump for assistance. It is compact (devoid of a large vacuum chamber) and the MC is separate from it (allowing you to use your existing MC if compatible re the two-stud fixing). See photo below of the set-up I have. It is hard to see but is the cast iron component behind the MC, the gold cylinder is its accumulator for when the engine isn't running, the rest of it is hard to see - I did say 'compact'. How easy sourcing an HB unit would be I don't know - they are an American 'thing' and sought after as they permit brake assistance where a lairy cam kills vacuum.




Another pic of HB below. MC is to the left, cast iron lump is HB.

 

[carat 3.6]

. How easy sourcing an HB unit would be I don't know - they are an American 'thing' and sought after as they permit brake assistance where a lairy cam kills vacuum.

Not a bad idea, we did get them over here on 90's BMW's like the e34 and e38. I did transfer one into the E30 when I v8 swapped it so it is definitely a possibility to adapt it into different vehicles.

 

[Bellow]

Not a bad idea, we did get them over here on 90's BMW's like the e34 and e38. I did transfer one into the E30 when I v8 swapped it so it is definitely a possibility to adapt it into different vehicles.

When I found HydroBoost on my Chevy it was the first I knew of it and assumed it was a GM 'thing'. Then saw it on other US produced vehicles and realised not GM specific. I had no idea that BMW used it. That might help with availability should the OP choose to pursue.

 

[WalterScott]

Thank you for the replies.
Update: no developments yet.
Another servo that would slot right in and accept my MC would be lovely, but what one? When talking with Pastparts, etc., no one can seem to recommend an alternative servo. There are plenty of 9-inch diameter servos out there, but what vacuum strength, return spring, etc.? Try to find one from a vehicle of similar weight, then maybe??? That is the technical advice I've received.
Fitting a remote servo is beyond me. I will text the mechanic and find out if there are any possibilities.
HydroBoost uses the power steering pump?
Opening the unit is beginning to appeal in some ways. Perhaps it could be an easy fix (that would be wonderful). Perhaps not.
I suggested to a couple of the reconditioning companies that I was more than willing to pay for an attempt to repair the servo, and that I understood it may return to me in parts, in a box. What with all the spares I imagine at their disposal, perhaps they may have the necessary seal or whatever for the fix, but no one would take it on. I'm not sure what to do next, and wonder if I'm missing something with the reluctance to take on the servo repair? Are the seals that difficult to find now? Perhaps a valve or a diaphragm? Or the 'widget'? Surely someone knows the way to the widget makers' forest lol? Kidding aside, I am going on holiday and shall return with my batteries recharged and continue with my quest.

 

[DSM10000]

Thank you for the replies.
Update: no developments yet.
Another servo that would slot right in and accept my MC would be lovely, but what one? When talking with Pastparts, etc., no one can seem to recommend an alternative servo. There are plenty of 9-inch diameter servos out there, but what vacuum strength, return spring, etc.? Try to find one from a vehicle of similar weight, then maybe??? That is the technical advice I've received.
Fitting a remote servo is beyond me. I will text the mechanic and find out if there are any possibilities.
HydroBoost uses the power steering pump?
Opening the unit is beginning to appeal in some ways. Perhaps it could be an easy fix (that would be wonderful). Perhaps not.
I suggested to a couple of the reconditioning companies that I was more than willing to pay for an attempt to repair the servo, and that I understood it may return to me in parts, in a box. What with all the spares I imagine at their disposal, perhaps they may have the necessary seal or whatever for the fix, but no one would take it on. I'm not sure what to do next, and wonder if I'm missing something with the reluctance to take on the servo repair? Are the seals that difficult to find now? Perhaps a valve or a diaphragm? Or the 'widget'? Surely someone knows the way to the widget makers' forest lol? Kidding aside, I am going on holiday and shall return with my batteries recharged and continue with my quest.

Cannot help with your quest but good luck and enjoy your holiday

 

[WalterScott]

Cannot help with your quest but good luck and enjoy your holiday

Cannot help with your quest but good luck and enjoy your holiday

Thank you