Benjamin had been married before he was married to Sarah, and assumed to be a little older than Sarah, so guess born about 1736.
His first two children take the names of his parents:

Name:    Benjamin Buckley
Event Type:    Baptism
Baptism Date:    25 Dec 1734
Baptism Place:    Oldham, St Mary, Lancashire, England
Father:    James Buckley
Mother:    Sarah Buckley
Reference Number:    GB127.L185/1/2
Abode: Waterhead Miln

He was married to Hannah, and had children in 1754,56,58 so this baptism in 1734 is about right.

Name: Benjamin Buckley
Event Type: Burial
Burial Date: 28 Aug 1777
Parish: Saddleworth, St Chad
Parish as it Appears: Saddleworth
Reference Number: O9/1/1/5
Item Number: 6
Archive Roll: 905
Text reads: Benjamin Buckley Clo'r (i.e. Clother) of Shelderslow
(no age or wife recorded)

Had been married before, so probably born before 1739.
Last child, John born 1776, so probably born after 1736.
therefore Born about 1737 +/- 2

Name: Sarah Buckley
Event Type: Burial
Burial Date: 7 Mar 1782
Parish: Saddleworth, St Chad
Parish as it Appears: Saddleworth
Reference Number: O9/1/4/1
Item Number: 6
Archive Roll: 909

Sarah Buckley widow of New Mill

Mary Buckley
Christening:  01 JUN 1762   Oldham, Lancashire, England
Parents:
  Father:  Benjamin Buckley
  Mother:  Sarah Ogden    

Name:    Mary Buckley
Baptism Date:    1 Jun 1762
Parish:    Oldham, Lancashire, England
Father's name:    Benjamin Buckley
Mother's name:    Sarah Buckley
Register Type:    Bishops Transcripts
Reference Number:    Drm/2/236a

Actual baprism record reads:
Mary daughter of Benjamin Buckley of Coldhurst high barn by Sarah his wife

Joseph Buckley
Christening:  03 MAR 1765   Oldham, Lancashire, England
Parents:
  Father:  Benjamin Buckley
  Mother:  Sarah Ogden 

Baprism record reads:
Joseph son of Benjamin Buckley of Holdend Weaver by Sarah his wife

Josiah Buckley
  Male    
Christening:  05 APR 1768   Oldham, Lancashire, England
Parents:
  Father:  Benjamin Buckley
  Mother:  Sarah Ogden 

Baptism record reads:
Josiah son of Benjamin Buckley of Holdend Weaver by Sarah his wife

Name: Josiah Buckley
Event Type: Burial
Age: 23
Birth Date: abt 1768
Burial Date: 25 Jul 1791
Parish: Oldham, St Mary
Reference Number: GB127.L185/1/4/3

Josiah Buckley of Chadderton Heights, Benjamin's son, died aged 23.

Name:    Benjamin Buckley
Baptism Age:    0
Event Type:    Baptism
Birth Date:    16 Nov 1770
Baptism Date:    25 Dec 1770
Baptism Place:    Bury, St Mary, Lancashire, England
Father:    Benjamin Buckley
Reference Number:    L215/1/1/5
Archive Roll:    670
Abode: Bury

No mother names are shown on these Bury baptisms.  This appears to be the only baptism for Benjmin and Sarah at Bury, and fits the gap between other births/baptisms.

Name:    Buckley
Death Date:    3 Feb 1772
Burial Place:    St. Mary The Virgin, Bury, Manchester
Father:    Benjamin Buckley
FHL Film Number:    559161
Reference ID:    Feb 1772

England & Wales Deaths 1837-2007
Buckley    Benjamin    
Born: 1870    
Died: 1872
Oldham, Lancashire, England

Anne Buckley
Christening:  11 MAR 1772   Saint Mary, Oldham, Lancashire
Parents:
  Father:  Benjamin Buckley
  Mother:  Sarah Ogden 

Baptism record reads: "Anne Daughter of Benjamin Buckley of Chaderton heights by Sarah his wife"

There is another Ann, daughter of James Buckley from Bory, baptised 25 Dec 1772 who died 1773.

Assumed to have died in Odham or Saddleworth, as next child to be baprised is also Ann.

Name: Ann Buckley 
Gender: Female 
Christening Date: 18 Apr 1773 
Christening Place: SADDLEWORTH,YORK,ENGLAND 
Father's Name: Benjn. Buckley 
Mother's Name: Sarah 
Indexing Project (Batch) Number: P00584-1 
System Origin: England-ODM 
GS Film number: 0558358, 0558359 
Reference ID: 

Ann dau of Benj'n Buckley Clo'r & Sarah his Wife of Sheldreslow

Place name appear to be same place as that of John's baptism of 1766, but diffieult to read that image either, although Sheldreslow appears next to Latham on 1841 census.

Lancashire Death indexes for the years: 1848
HALL    Ann    78    Delph, Saddleworth    Oldham    DEL/5/30

Aged 65 in 1841, born Lancashire
Aged 75 in 1851, born Latham (or Lytham), Yorkshire
Aged 77 in Jan 1853 (when died)

Baptism: "John Son of Benjamin Buckley Clo (i.e. Clothier) & Sarah his wife of Shelderslow"

1851 census record clearly states John (75) is from "Yorks Latham", whilst Mary (70) is from "Lancashire Bolton".  He was 77 when he died (so born Jan or Feb 1776).

Latham is a hamlet in Saddleworth. John and his sister Ann were baptised here.  An article in the the Leeds Mercury, on Saturday, April 25, 1840 advertised for sale:
"FOUR DWELLING-HOUSES with Gardens and Appurtenances, and small CROFT, containing 2 Roods and 8 Perches, situate at Latham, in Saddleworth aforesaid, and now in the Occupations of Ann MAYALL, Samuel DIXSON, Thomas WHITEHEAD, and Others. Also a CHIEF RENT of £1 14s. 7d per Annum, issuing out of, and secured upon another House and Premises, at Latham aforesaid.

There about 30 John Buckley's from Yorkshire born 1776 +/- 5, and almost all from Saddleworth.  By trying to match parents to childrens names, Benjamin and Sarah fit quite well, but obviously not confirmed.

Name: John Buckley
Event Type: Baptism
Baptism Date: 2 Jun 1776
Parish: Saddleworth, St Chad
Parish as it Appears: Saddleworth
Father's Name: Benjamin Buckley
Mother's name: Sarah Buckley
Abode: Sheldreslow
Reference Number: O9/1/1/5
Item Number: 6
Archive Roll: 905

The marriage for John Buckley and Mary Crook, shows them both from Oldham.  John's parents were from Oldham, and his siblings baptised in Oldham, which explains the discrepency.
 

Six Bolton deaths to choose from:  Was alive in 1851 and died by 1861.
Jeff Buckley has his death certificate, and has his death as 27-Jan-1853.

BUCKLEY, JOHN        76 
GRO Reference: 1853  M Quarter in BOLTON UNION 
Volume 08C  Page 209

Name: BUCKLEY, John
Age: 76    
Sub-District: Eastern Bolton
Registered at: Bolton
Reference: EB/21/206

During his time in Bolton he lived at 34 Crook Street and this is the address given on his death cert. with occupation as an 'Oil Cloth Maker'

Died before Tonge cemetery opened in 1856, so not buried with wife Mary.  Does not appear to be at St Peter's Parish church either!

No Will or probate indexed for John Buckley (although there is for John Buckley, Gentleman of Saddleworth in 1858), possibly a cousin.