LHM seal guide - help needed
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  1. #1
    Fellow Frogger! Big Frog's Avatar
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    Default LHM seal guide - help needed

    Hi All,
    Sorry for the stupid question in advance.
    putting together my rebuilt D Special 74 motor that is going into a 70 D special. There are a bunch of reconditioned and new parts and obviously a number of hook ups to make with hydraulic connections.
    I have the 814-1, 814-2 manuals and the parts manual, also the Cit Hydraulics Course notes, but I need a poke in the right direction when it comes to selecting the right LHM seal to insert in a new connection.
    I have a bunch of new seals from different suppliers (Darrin in Uk & Franzose, and mister Parker) fresh in packets. Obviously some are big and some small. Two of the smaller ones will fit for instance on the front caliper brake connections. But they are different sizes, and one has a green stripe.

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    How does one differentiate the LHM seals ?
    I have been back and forth thru the manuals and can't see where they are listed size wise for each junction.
    I did see the thread from late last year that had a chart in which it showed diagrams (great) but referenced with a part number.. (not a diameter and length of the new unfitted seal)
    How do I measure a new LHM seal from a packet and decide that it either the right one for the join?
    Am I missing something in the manuals?
    cheers

    Steve

  2. #2
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    LHM seals usually have a green marking. A stripe or band. Sometimes they're even completely green - like a certain frog.

    Generally, and others may correct me, if the seal is a comfortable fit on the pipe then it is the right size. It will also fit comfortably into the mounting point for the pipe. A 6.35mm diameter pipe takes the larger seal and the other two sizes work down from there. You will use more of the larger seals than small.

    It is usually better to put the seal on the pipe then insert it into its mounting point rather than try to get the pipe to wiggle into an inserted seal. The ease of ability to carefully start the thread off into the insertion point is inversely proportional to your ability to see and/or touch the location of the union. Always get it started carefully before applying a pipe spanner. Swear frequently.
    Craig K
    2009 C5 HDi Exclusive

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    Steve,

    First off it would be of great help to know exactly which seals you are referencing. Second, the parts books do give, typically, the exact size in mm of the seals being referenced. For example, the top seals for the pistons assembly in a 7 piston HP pump are 15.7x21.1x2.7 (ID/OD/x-section). As they are round 15.7 + 2x2.7 = 21.1.

    Any rubber seals that are put in a dynamic situation in an LHM car (IOW seals that have something sliding against the inside or on the outside edge) will be marked (if factory) with a green dot/strip. Seals in a static situation can be marked either with a green mark or a white mark. Any rubber seal that provides sealing 'squeeze' (if you will) for a Teflon sealing ring (PS/Suspension cylinders and some other places) should also be marked in green. The green only signifies that the rubber is Buna-N (nitrile based). A 'white' marked seal signifies that it is made of Neoprene or possibly Norprene (a neoprene/plastic composite)

    Now, most all of the seals used can be quite successfully replaced by standard AS (American Standard) sized seals. However a bit of thinking on now the seals are going to be used is needed to get the right ones.

    Most chemical compatibility guides use a 1 through 4 rating for the various rubber compounds and chemicals listed in those guides. A rating of A(1)=compatible, B(2)=fair resistance, C(3)=Doubtful resistance and D(4)=not suitable. Some charts will also include an 5(X) listing - signifies that insufficient data exists to make a determination. In any chart you might want to consult Neoprene will have a B(2) rating for both mineral oil based hydraulic fluids (LHM for example) and DOT 3/4 gylcol based brake fluids (LHS).

    With regards to the front brakes. The rubber seal used for the actual brake pistons is quite large - 59.2x69.8x5.3 mm to be exact (size gotten from 648). OTOH it can be quite successfully replaces by an AS 332 sized 0-ring. The small 0-rings in the various sealing plates used through out the car have a dimension (again from 648) of 4.2x8x1.9mm. Either AS 008 or metric 4x8x2 (easily sourced) rings work just fine

    Steve

  4. #4
    Fellow Frogger! Big Frog's Avatar
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    Default sample seals

    LHM seal guide - help needed-image.jpg
    thanks for the replies.
    here is a pic of the seals i have.
    The middle one has no stripe. For arguments sake I can get the top two onto the pipe that goes from one side of the caliper to the other. But one must be wrong?
    My query is mainly about the seals used where a pipe goes into a fitting. The piston seals for the calipers and the felts are more easily identified and I have those replacements.
    I guess the ones i'm looking at presently are:
    - the pipes that feed the calipers
    - the cross over pipe on the calipers (pressure equalisation pipe? on each caliper)
    - pump to the regulator, both ends
    - the outlet of the regulator to the pipe

    Steve

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    Quote Originally Posted by Big Frog View Post
    Click image for larger version. 

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    thanks for the replies.
    here is a pic of the seals i have.
    The middle one has no stripe. For arguments sake I can get the top two onto the pipe that goes from one side of the caliper to the other. But one must be wrong?
    My query is mainly about the seals used where a pipe goes into a fitting. The piston seals for the calipers and the felts are more easily identified and I have those replacements.
    I guess the ones i'm looking at presently are:
    - the pipes that feed the calipers
    - the cross over pipe on the calipers (pressure equalisation pipe? on each caliper)
    - pump to the regulator, both ends
    - the outlet of the regulator to the pipe

    Steve
    Steve,

    Look in 648. Specifically section 3 - subcategory 394 page 8 (3-394/8). It lists the 3 different line sleeves used on all D models - gives you the factory recommended length/ID and OD. The majority are the small ones - they are for all of the lines that use the 9mm securing nuts (9x1.25 thread) - and are for the 4.5mm OD steel pipe. You will have two larger ones. They both are for the 6.3mm OD pipes but do have different OD for the sleeves. The smaller of the OD sleeve is for the outlet from the HP pump to the PR. The larger is for the feed pipe from the brake accumulator to the brake system controller.

    The one pictured with out a marking, I personally, would not use as you have no idea of the rubber compound unless you know who supplied it.

    Steve

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    Fellow Frogger! Big Frog's Avatar
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    Ok
    I'm thinking the smaller black one is miss supplied and is maybe a LHS seal.
    The green striped smaller one fits and is in line with Craig's 'comfortable fit theory'.
    I'm studying the 648 Manual closely.

    BTW
    Can anyone shine some light on these parts/ pages from the 648 manual, they don't line up with my engine and not parts that I have seen - so I'm guessing they are off another version / model?

    LHM seal guide - help needed-blank.jpg
    Item 4 - Blanking Plate? This is an attachment for a coolant pipe on mine

    LHM seal guide - help needed-distance.jpg
    Item 25 is a Distance washer that seems to go on Item 4 - Locating Pin (the locating pin I have, not sure about the washer?)

    Steve
    Attached Thumbnails Attached Thumbnails LHM seal guide - help needed-starter-stud.jpg  
    Last edited by Big Frog; 15th February 2016 at 11:21 AM.

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    Quote Originally Posted by Big Frog View Post
    BTW
    Can anyone shine some light on these parts/ pages from the 648 manual, they don't line up with my engine and not parts that I have seen - so I'm guessing they are off another version / model?

    Click image for larger version. 

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    Item 4 - Blanking Plate? This is an attachment for a coolant pipe on mine

    Steve
    Yes, a blanking plate for cars delivered without a heater, yours will have part #9 as seen here. . .



    I can't help with the second part of your question.

    Cheers
    Chris
    Attached Thumbnails Attached Thumbnails LHM seal guide - help needed-heater-pipe-9.jpg  
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  8. #8
    BVH Roger Wilkinson's Avatar
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    Stick the noname seal in a jar of LHM for a few weeks and see what happens to it.

    Roger

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    Quote Originally Posted by Big Frog View Post
    Ok
    I'm thinking the smaller black one is miss supplied and is maybe a LHS seal.
    The green striped smaller one fits and is in line with Craig's 'comfortable fit theory'.
    I'm studying the 648 Manual closely.

    BTW
    Can anyone shine some light on these parts/ pages from the 648 manual, they don't line up with my engine and not parts that I have seen - so I'm guessing they are off another version / model?

    Click image for larger version. 

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ID:	80689
    Item 4 - Blanking Plate? This is an attachment for a coolant pipe on mine

    Click image for larger version. 

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ID:	80690
    Item 25 is a Distance washer that seems to go on Item 4 - Locating Pin (the locating pin I have, not sure about the washer?)

    Steve

    Steve,

    When looking in the parts books you also need to be aware of the little notations (mostly in line with the part description and number).

    In the case of #25 you will find that it only applies to BVH cars (Citromatic). A BVM car will not have it. The same is true for the blanking plate. It was only applicable to DV and DLF models up to 7/72. Another example of this is item #13 in 1-112/1. It will only be found on IE cars.

    Steve

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    Is item 25 a snap ring to stop the dowel falling out the back of the hole?

    Quote Originally Posted by Roger Wilkinson View Post
    Stick the noname seal in a jar of LHM for a few weeks and see what happens to it.

    Roger
    Try it in brake fluid and if it swells, you know it was OK for LHM. Like testing matches.

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    Quote Originally Posted by David S View Post
    Is item 25 a snap ring to stop the dowel falling out the back of the hole?



    Try it in brake fluid and if it swells, you know it was OK for LHM. Like testing matches.


    Why nut just put it some LHM for a couple of weeks. If nothing happens you know it is safe to use

    Steve

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    Thanks for all the replies - can proceed now, will test the small black ones for interest.

    cheers
    Steve

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    Dear Brains Trust,
    Progress is being made on the engine reassembly, brakes are re sealed and re felted, and trying to ensure I have all the bits/ seals /fasteners etc. A disassembled D takes up plenty of room!

    So question for today is - Why do I have these?
    LHM seal guide - help needed-copper.jpg
    I have three, and as much as I scroll back and forward thru 648, I can't see them? (648 and I are not friends)
    Steve

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    Quote Originally Posted by Big Frog View Post
    Dear Brains Trust,
    Progress is being made on the engine reassembly, brakes are re sealed and re felted, and trying to ensure I have all the bits/ seals /fasteners etc. A disassembled D takes up plenty of room!

    So question for today is - Why do I have these?
    Click image for larger version. 

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Views:	184 
Size:	82.8 KB 
ID:	80733
    I have three, and as much as I scroll back and forward thru 648, I can't see them? (648 and I are not friends)
    Steve
    Steve

    This really is just an educated guess, but they sort of look like brass compression sleeves (and not a Cit part). If that is what they really are they are used to make very tight fitting connections (with the correct nut) for mild steel or copper pipe. They can be used, in emergencies, to make repairs to the hydraulic lines in the car. Done correctly they will hold. However it is only an emergency repair. The affected line would need to be replaced ASAP with the correct Citroen designed unit.

    Steve

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    Quote Originally Posted by Citroenfan View Post
    Steve

    This really is just an educated guess, but they sort of look like brass compression sleeves (and not a Cit part). If that is what they really are they are used to make very tight fitting connections (with the correct nut) for mild steel or copper pipe. They can be used, in emergencies, to make repairs to the hydraulic lines in the car. Done correctly they will hold. However it is only an emergency repair. The affected line would need to be replaced ASAP with the correct Citroen designed unit.

    Steve
    I'm with Steve on this. Those are STRICTLY a get-you-home item. Don't toss them, they're worth keeping. Just know that you don't want to rely on that for a permanent repair.
    The measure of your character isn't what you do when people are watching- it's what you do when they aren't watching.

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    These look rather like a 1/2" plumbing olive to me. Crept in there from a trip to Masters (Cough!!) maybe? There is no hydraulic pipe that large in a DS and you'd want to be sure anything like this is the correct profile for any compression fitting you plan to use. I know those compression fittings are not pretty and it would not be your first choice, but if chosen correctly and from a decent manufacturer, they should be reliable even in permanent use. They are certainly designed for that purpose, although you may have to think about the fluid vs fitting material long-term.

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    Thanks for the reply, these were supplied to me when I received an overhauled hydraulic pump, they were in a small zip lock bag, so I assumed they had something to do with that part or something else I had mentioned to the overhauler at the time.
    Why they were supplied will remain a mystery.
    Cheers
    Steve

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    Quote Originally Posted by David S View Post
    These look rather like a 1/2" plumbing olive to me. Crept in there from a trip to Masters (Cough!!) maybe? There is no hydraulic pipe that large in a DS and you'd want to be sure anything like this is the correct profile for any compression fitting you plan to use. I know those compression fittings are not pretty and it would not be your first choice, but if chosen correctly and from a decent manufacturer, they should be reliable even in permanent use. They are certainly designed for that purpose, although you may have to think about the fluid vs fitting material long-term.
    Fluid would not be a problem as they are brass - and, yes, they will last OK if done correctly. However that is the operative word........Here in the US have seen more than a few times where those connections have not lasted. Not a pretty sight.

    As to why they arrived with a re-sealed pump is anyone's guess. Possible that someone in the shop's shipping area included them by mistake? Bottom line is, as David observed, that they are not a Cit nor D series part.

    Steve

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    Quote Originally Posted by Big Frog View Post
    Thanks for the reply, these were supplied to me when I received an overhauled hydraulic pump, they were in a small zip lock bag, so I assumed they had something to do with that part or something else I had mentioned to the overhauler at the time.
    Why they were supplied will remain a mystery.
    Cheers
    Steve
    As a stand alone item they are useless other than perhaps decoration, I note de Franzose sell a hydraulic compression joint to facilitate a repair in a line - suitable for 3.5mm and 3.75mm?
    https://www.franzose.de/en/Citroen-D...epfe/ANR32388/



    Perhaps you had mentioned damage to the pipe fitting and the compression joint was supplied as a possible solution? Personally I would be replacing the whole line especially as you have good access with the motor yet to be fitted.

    Not a Citroen part. . .

    Cheers
    Chris
    74 D(very Special) >>Rejuvenation Thread<<
    08 C5 X7 HDi very Noir



    "Déesse" Roland Barthes, 'Mythologies', 1957

    The Déesse has all the characteristics of one of those objects fallen from another universe that fed the mania for novelty in the eighteenth century and a similar mania expressed by modern science fiction: the Déesse is first and foremost the new Nautilus.

    (Umberto Eco [Ed], The History of Beauty, Rizzoli, NY, 2004)

  20. #20
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    Have seen those also. But given that the two pipe sizes in D's are 4.5mm and 6.3mm - a fitting for a 3.5mm pipe (CX and others) is sort of useless for any sort of repair in a D . A standard 3/16" (ID 4.73mm) fitting can be made to work if the nuts are really torqued down and a standard 1/4" works fine for the 6.3mm pipes.

    Steve

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    I don't see how the bagged olives are related to a hydraulic pump. Most likely a picking error, although it's possible they were intended for the tubing on a set of A/C condensers jammed down under each headlamp. These do use copper tubing about that size, but it is not a Citroen fitting.

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