Removing R4 compressor questions - PeachParts Mercedes-Benz Forum

funola · #1 08-10-2016, 09:17 AM

The FSM procedure to remove the R4 says first step is to remove the clutch, then the belt, then the clamps for the hoses then the R4 mounting hardware, the manifold pipe/hoses are to be left in place. I wish it gives a reason.

1. Why does the clutch have to be removed first? Is it a clearance issue?

2. Why is the manifold left on? Is is to prevent oil from spilling? It would seem easier to remove the R4 if the unwieldy manifold is removed and out of the way first.

Demothen · #2 08-10-2016, 09:32 AM

The clutch & pulley don't need to be removed. There's plenty of room.

I think that the manifold is left on to prevent oil spillage, and later on it's nice to have it removed so you can oil the new compressor. I removed my compressor first, then the manifold, then installed them as a unit. I think it's nice to pull the manifold so you can get everything really clean and install the new sealing washers on the bench, then add oil.

ambush276 · #3 08-10-2016, 10:51 AM

how do you remove the manifold from the hose? Or are you removing the hoses as well?

Demothen · #4 08-10-2016, 11:30 AM

Quote:

Originally Posted by ambush276

how do you remove the manifold from the hose? Or are you removing the hoses as well?

The FSM calls the metal bit of the manifold + the high pressure hose the "manifold" - so that's all removed as an assembly (There's a few other clamps you need to remove in order from the hose to come out). In my case, I'm not going to be reusing the manifold since I'm switching to a Sanden, however I will be rebuilding some of the suction hoses by cutting off the ferule and crimping in new barrier hose. Hopefully I'll be getting to that this weekend, and I plan to write up a DIY on the job.

Edit: the suction side hose is connected with a fitting that's buried underneath the cruise control actuator. It's not in a very easy place to get tools and leverage for, fortunately mine was not excessively tight

funola · #5 08-10-2016, 01:09 PM

Does the compressor come out the bottom? If so did you have to undo the rubber transmission cooler line?

How about the short hose, from the condenser to the high pressure discharge pipe, mounted with a bracket/ 17 mm nut to block and another bracket to oil pan? Did you have to undo the fitting for that hose and remove it? Or can it stay on and come out with the compressor? The fitting is under the air cleaner by the alternator, space lppks tight to get wrenches on it.

Demothen · #6 08-10-2016, 01:21 PM

The compressor drops out from the bottom. I don't think we disconnected the trans cooler lines when we pulled it, but we misrouted the high side line when we reinstalled it, so ended up disconnecting the trans cooler lines, and I decided to replace them while we were at it.

The short condenser to high side hose did not have to come out, I don't think. Mine was in rough shape so I replaced it though. You might be able to disconnect the condenser end and take it off as a unit. The bracket is a huge pain to get to. I'm not looking forward to disconnecting it for the second compressor install. I honestly don't remember the exact details, but that was probably one of the more difficult things to access on the entire system. I think I was able to get a wrench on it from under the car. I think the bracket is eliminated with my Sanden kit, and the hose is all one piece to the condenser.

funola · #7 08-10-2016, 01:38 PM

That PITA bracket is held captive by 2 Allen head bolts that go through the oil pan and two 10 mm nuts. Both Allen heads must be removed. The 17 mm nut is removed from the bottom with a socket and ratchet on a short extension. Good that you will be eliminating that stupid contraption with your kit. I may make a custom hose to eliminate mine.

funola · #8 08-10-2016, 02:35 PM

Found this exc. pdf
http://www.peachparts.com/shopforum/attachments/diesel-discussion/129114d1430754844-sanden-retrofit-installation-guide-w123-61x-sanden-ac-compressor-conversion-part-i-ver01-00.pdf

by forum member Mahone Bay on Rollguys Sanden kit which has nice step by step instructions with pics on R4 removal.

BillGrissom · #9 08-10-2016, 05:20 PM

Easier to leave the manifold-HP hose in the car. If the car is on ramps, there is plenty of room to install the seal washers after the new R4 is in. But wait until the R4 is back on before oiling it by pouring down the top of the suction tube (disconnect nut up high). However, I agree w/ the plan to replace the HP hose and get rid of the silly run up the R side of the engine and the bracket that bolts to the top of the upper oil pan. I did so, running straight over to the condenser and bending the factory fitting at the condenser down to match. That will free up space and places to trap gunk. You will then find changing the turbo and air cleaner oil drain stub O-rings easy and adjusting the alternator (no EGR also helps a lot). BTW, the AC hose fittings all have circumferential O-rings so don't go crazy tightening the nuts. All you need is enough so they don't unscrew themselves under vibration.

If replacing hose (wise, I did), I recall the suction hose is -12 size and HP hose is -10. Use only "barrier" hose since less leakage and better compatibility w/ non R-12 refrigerants. If you want smaller OD, buy "reduced barrier" size. An AC hose crimper makes factory-looking crimps on new ferrules (I did), but Oeticker step-less ear clamps would look nice too and only require "nail puller" pliers to crimp. I bought all on ebay. You might pay $120 for a used ferrule crimper kit but can sell for $120 when done.

Demothen · #10 08-10-2016, 08:21 PM

BillGrissom,
Did you reuse any of the original metal tubing? If so, how did you cut the old ferrules off? It looks like some of them may have been brazed to the lines? Did you just cut that end off as flush as possible to the tube?

ROLLGUY · #11 08-10-2016, 09:14 PM

Quote:

Originally Posted by Demothen

BillGrissom,
Did you reuse any of the original metal tubing? If so, how did you cut the old ferrules off? It looks like some of them may have been brazed to the lines? Did you just cut that end off as flush as possible to the tube?

The problem with just grinding off the sleeves (ferrules), is that the factory fittings are "bead lock", meaning the sleeve is locked into the fitting. If the sleeve is ground or cut off, a new sleeve is only clamping the hose, and not connected to the fitting. This type of fitting has less aggressive barbs than a non-bead lock fitting. I have had experience with the hose coming off because the sleeve is not captured on the fitting (higher pressures with 134a). If you cut off the old hose and sleeve, a new barb can be welded on, and will hold the hose without the sleeve being part of the fitting (coarser barb).

Demothen · #12 08-11-2016, 09:27 AM

Rollguy,
How much of a problem do you think it is not welding on new fittings on the suction side lines only? Those should be subject to less than 100 psi right?

funola · #13 08-11-2016, 09:54 AM

Quote:

Originally Posted by ROLLGUY

The problem with just grinding off the sleeves (ferrules), is that the factory fittings are "bead lock", meaning the sleeve is locked into the fitting. If the sleeve is ground or cut off, a new sleeve is only clamping the hose, and not connected to the fitting. This type of fitting has less aggressive barbs than a non-bead lock fitting. I have had experience with the hose coming off because the sleeve is not captured on the fitting (higher pressures with 134a). If you cut off the old hose and sleeve, a new barb can be welded on, and will hold the hose without the sleeve being part of the fitting (coarser barb).

I am new to beadlock fittings so pardon me if I am not describing it right. Isn't the "beadlock" the "bead" on the male insert where the o-ring seats which also forms a stop against its female mating half? The sleeve or ferrule is for crimping the hose and has nothing to do with the bead.

The Mercedes AC fittings are all beadlock fittings where the sleeve or ferrule is part of the entire fitting and not a replaceable part. If one tries to grind off the Mercedes ferrule and replace with a ferrule with a barb hole in it, it will be a much weaker crimp.

funola · #14 08-11-2016, 10:46 AM

Instead of weld-on crimp ferrules, it'd be better to replace the entire fitting with something like this kit

Beadlock A C All Steel Fittings Female Straight 45 90 Degree 6 8 10 9 PC | eBay

This kit is just an example and does not have all the pieces needed.

Demothen · #15 08-11-2016, 10:48 AM

FYI the reason I'm asking is my welder is terrible (both the welding machine, and the person operating it - me). Would there be a way to braze the ferrule in place over the existing hardline? Or would I possibly be able to buy new beadlock or barbed fitting that would slip over the hardline and allow me to braze it in place?
I'm rebuilding the suction side hoses, fyi - I need to reuse the special fitting at the output side of the condenser, as well as the hardline that runs across the top of the engine bay. The other ends I'll be replacing with new fittings, so that's not a concern.